Timer: Off
Random: Off
1. What is the electronic configuration of sodium (Na)?
ⓐ. $[Ne], 3s^1$
ⓑ. $[Ar], 4s^1$
ⓒ. $[He], 2s^2, 2p^6$
ⓓ. $[Ne], 2s^2, 2p^6, 3s^2$
Correct Answer: $[Ne], 3s^1$
Explanation: Sodium (Na) belongs to Group 1 of the periodic table, also known as alkali metals. Its atomic number is 11, and its electronic configuration is $[Ne], 3s^1$, meaning it has one electron in its outermost shell. This configuration makes sodium highly reactive.
2. Which of the following statements is true for alkali metals in Group 1?
ⓐ. They have high ionization enthalpy.
ⓑ. They have a high density.
ⓒ. They are non-reactive with water.
ⓓ. They have low melting and boiling points.
Correct Answer: They have low melting and boiling points.
Explanation: Alkali metals, such as sodium and potassium, have low melting and boiling points compared to most metals. This is due to the weak metallic bonding caused by their single outermost electron. They are also highly reactive with water.
3. Which of the following is the primary reason for the high reactivity of alkali metals?
ⓐ. Their large atomic size
ⓑ. Their low ionization enthalpy
ⓒ. Their high melting points
ⓓ. Their strong metallic bonds
Correct Answer: Their low ionization enthalpy
Explanation: Alkali metals are highly reactive because they have low ionization enthalpy, which means they can easily lose their single outer electron. This makes them highly reactive, particularly with water and halogens.
4. What is the electronic configuration of calcium (Ca)?
ⓐ. $[Ne], 3s^2, 3p^6, 4s^2$
ⓑ. $[Ar], 4s^2$
ⓒ. $[Ne], 3s^2, 3p^6$
ⓓ. $[Kr], 5s^2$
Correct Answer: $[Ar], 4s^2$
Explanation: Calcium (Ca) belongs to Group 2 of the periodic table (alkaline earth metals) with an atomic number of 20. Its electronic configuration is $[Ar], 4s^2$, meaning it has two electrons in its outermost shell.
5. Which of the following compounds is commonly used as a laxative?
ⓐ. $NaCl$
ⓑ. $NaOH$
ⓒ. $MgSO_4$
ⓓ. $CaCO_3$
Correct Answer: $MgSO_4$
Explanation: Magnesium sulfate ($MgSO_4$) is commonly used as a laxative due to its ability to draw water into the intestines, thereby promoting bowel movements. Sodium chloride ($NaCl$), sodium hydroxide ($NaOH$), and calcium carbonate ($CaCO_3$) do not have this effect.
6. What is the trend in the atomic radius of alkali metals as we move down Group 1?
ⓐ. The atomic radius decreases.
ⓑ. The atomic radius increases.
ⓒ. The atomic radius remains the same.
ⓓ. The atomic radius becomes unpredictable.
Correct Answer: The atomic radius increases.
Explanation: As we move down Group 1, the alkali metals become larger because the number of electron shells increases. This leads to an increase in atomic size, despite the increase in nuclear charge.
7. Which of the following reactions does sodium (Na) undergo with water?
ⓐ. $Na + H_2O \rightarrow NaOH + H_2$
ⓑ. $Na + 2H_2O \rightarrow NaOH + H_2O$
ⓒ. $Na + 2H_2O \rightarrow NaOH + 2H_2$
ⓓ. $Na + H_2O \rightarrow NaH + O_2$
Correct Answer: $Na + H_2O \rightarrow NaOH + H_2$
Explanation: Sodium reacts vigorously with water, producing sodium hydroxide ($NaOH$) and hydrogen gas ($H_2$). The reaction is highly exothermic, often resulting in the release of enough heat to ignite the hydrogen gas.
8. Why is lithium (Li) considered anomalous compared to other alkali metals?
ⓐ. It has a high atomic mass.
ⓑ. It forms basic oxides.
ⓒ. It has high ionization energy and forms covalent compounds.
ⓓ. It does not react with water.
Correct Answer: It has high ionization energy and forms covalent compounds.
Explanation: Lithium (Li) is considered anomalous due to its high ionization energy and the tendency to form covalent bonds, unlike other alkali metals that typically form ionic compounds. This is a result of its small size and high charge density.
9. What is the hydration enthalpy of alkali metals like?
ⓐ. It increases as we move down the group.
ⓑ. It decreases as we move down the group.
ⓒ. It remains constant across the group.
ⓓ. It fluctuates irregularly.
Correct Answer: It decreases as we move down the group.
Explanation: Hydration enthalpy refers to the heat released when ions are hydrated. For alkali metals, hydration enthalpy decreases as we move down the group due to the increasing size of the ions, which reduces the attraction between the ions and water molecules.
10. What is the common use of calcium hydroxide ($Ca(OH)_2$)?
ⓐ. To treat indigestion.
ⓑ. As a pesticide.
ⓒ. To make plaster of Paris.
ⓓ. As a disinfectant.
Correct Answer: As a disinfectant.
Explanation: Calcium hydroxide, also known as slaked lime, is commonly used as a disinfectant in water treatment and as a bleaching agent. It is not typically used for indigestion or as a pesticide. Plaster of Paris is made from calcium sulfate, not calcium hydroxide.
11. Which of the following represents the electronic configuration of potassium (K)?
ⓐ. $[Ne], 3s^2, 3p^6, 4s^1$
ⓑ. $[Ar], 4s^1$
ⓒ. $[Ar], 4s^2, 3d^{10}$
ⓓ. $[Ne], 3s^2, 3p^6, 4s^2$
Correct Answer: $[Ne], 3s^2, 3p^6, 4s^1$
Explanation: Potassium (K) belongs to Group 1 of the periodic table, so its electronic configuration is $[Ne], 3s^2, 3p^6, 4s^1$. This means it has one electron in its outermost shell in the $4s$ orbital.
12. Which alkali metal has the following electronic configuration: $[Ne], 3s^2, 3p^6, 4s^1$?
ⓐ. Sodium (Na)
ⓑ. Potassium (K)
ⓒ. Lithium (Li)
ⓓ. Rubidium (Rb)
Correct Answer: Potassium (K)
Explanation: The electronic configuration $[Ne], 3s^2, 3p^6, 4s^1$ corresponds to potassium (K), an alkali metal with an atomic number of 19. It has one electron in the $4s$ orbital, which makes it highly reactive.
13. What is the valence electron configuration of lithium (Li)?
ⓐ. $[He], 2s^2$
ⓑ. $[Ne], 3s^2, 3p^1$
ⓒ. $1s^2, 2s^1$
ⓓ. $[He], 2s^1$
Correct Answer: $[He], 2s^1$
Explanation: Lithium (Li) has an atomic number of 3, and its electronic configuration is $[He], 2s^1$. It has one valence electron in the $2s$ orbital, making it a highly reactive alkali metal.
14. Which of the following electronic configurations is correct for an alkali metal?
ⓐ. $[Ne], 3s^2, 3p^6, 4s^1$
ⓑ. $[He], 2s^1$
ⓒ. $[Ne], 3s^2, 3p^1$
ⓓ. $[Kr], 5s^2, 4d^{10}$
Correct Answer: $[Ne], 3s^2, 3p^6, 4s^1$
Explanation: The configuration $[Ne], 3s^2, 3p^6, 4s^1$ corresponds to potassium (K), an alkali metal. Alkali metals have a characteristic $ns^1$ configuration in their outermost shell, making them highly reactive.
15. Which of the following alkali metals has the highest atomic radius?
ⓐ. Lithium (Li)
ⓑ. Sodium (Na)
ⓒ. Potassium (K)
ⓓ. Rubidium (Rb)
Correct Answer: Rubidium (Rb)
Explanation: As we move down Group 1 of the periodic table, the atomic radius increases. Rubidium (Rb), being the heaviest alkali metal in the group, has the largest atomic radius among the options.
16. What is the common characteristic of all alkali metals in terms of their electronic configuration?
ⓐ. They have an electron in the $p$ orbital.
ⓑ. They all have a full $s$ orbital.
ⓒ. They have one electron in the outermost $s$ orbital.
ⓓ. They all have a filled $d$ orbital.
Correct Answer: They have one electron in the outermost $s$ orbital.
Explanation: All alkali metals have the general electronic configuration of $ns^1$ in their outermost shell, where $n$ is the principal quantum number, making them highly reactive.
17. Which of the following is the correct electronic configuration of rubidium (Rb)?
ⓐ. $[Kr], 5s^1$
ⓑ. $[Kr], 5s^2, 4d^{10}$
ⓒ. $[Xe], 6s^1$
ⓓ. $[Kr], 5p^1$
Correct Answer: $[Kr], 5s^1$
Explanation: Rubidium (Rb) belongs to Group 1 of the periodic table, and its atomic number is 37. Its electronic configuration is $[Kr], 5s^1$, with one electron in the $5s$ orbital.
18. How does the ionization energy of alkali metals change as we move down Group 1?
ⓐ. It increases.
ⓑ. It decreases.
ⓒ. It remains the same.
ⓓ. It fluctuates.
Correct Answer: It decreases.
Explanation: As we move down Group 1, the ionization energy decreases. This is because the atomic size increases, and the outermost electron is farther from the nucleus, making it easier to remove.
19. What happens to the reactivity of alkali metals as we move down the group?
ⓐ. Reactivity decreases.
ⓑ. Reactivity remains the same.
ⓒ. Reactivity increases.
ⓓ. Reactivity fluctuates.
Correct Answer: Reactivity increases.
Explanation: As we move down Group 1, the reactivity of alkali metals increases. This is due to the increasing size of the atoms, which makes it easier for the outermost electron to be lost.
20. Which alkali metal has the lowest ionization energy?
ⓐ. Lithium (Li)
ⓑ. Sodium (Na)
ⓒ. Potassium (K)
ⓓ. Rubidium (Rb)
Correct Answer: Rubidium (Rb)
Explanation: Rubidium (Rb) has the lowest ionization energy among the alkali metals because it has the largest atomic size, which means the outermost electron is more easily removed compared to the other alkali metals.
21. Which of the following is the most abundant alkali metal in the Earth’s crust?
ⓐ. Lithium (Li)
ⓑ. Sodium (Na)
ⓒ. Potassium (K)
ⓓ. Rubidium (Rb)
Correct Answer: Sodium (Na)
Explanation: Sodium (Na) is the most abundant alkali metal in the Earth’s crust, found primarily in the form of salts such as sodium chloride (NaCl), commonly known as table salt. Sodium is widely distributed in nature and is also present in seawater. Its abundance in nature is much higher than lithium, potassium, or rubidium.
22. Where can potassium (K) typically be found in nature?
ⓐ. In seawater
ⓑ. In volcanic ash
ⓒ. In the Earth’s atmosphere
ⓓ. In the form of minerals like feldspar
Correct Answer: In the form of minerals like feldspar
Explanation: Potassium (K) is found abundantly in the Earth’s crust, primarily in minerals such as feldspar and silicate minerals. It is also present in seawater, but in smaller concentrations compared to sodium. Potassium is not typically found in the atmosphere or volcanic ash in significant amounts.
23. Which compound is the primary source of sodium in nature?
ⓐ. NaCl (rock salt)
ⓑ. NaOH (caustic soda)
ⓒ. Na₂CO₃ (soda ash)
ⓓ. NaHCO₃ (baking soda)
Correct Answer: NaCl (rock salt)
Explanation: Sodium is primarily found in nature in the form of sodium chloride (NaCl), commonly known as rock salt. It is widely distributed in seawater and also found in large deposits in the Earth’s crust. NaCl is the main natural compound from which sodium is extracted for various industrial and chemical applications.
24. Which of the following is the most common source of lithium in nature?
ⓐ. Silica
ⓑ. Water
ⓒ. Lithium-bearing minerals like spodumene
ⓓ. Seawater
Correct Answer: Lithium-bearing minerals like spodumene
Explanation: Lithium is most commonly found in nature in lithium-bearing minerals such as spodumene, petalite, and lepidolite. These minerals are primarily mined for the extraction of lithium. Lithium is also present in small quantities in seawater, but it is primarily extracted from minerals rather than directly from water.
25. Where is rubidium (Rb) most commonly found in nature?
ⓐ. In seawater
ⓑ. In feldspar minerals
ⓒ. In the Earth’s atmosphere
ⓓ. In specific radioactive minerals
Correct Answer: In feldspar minerals
Explanation: Rubidium (Rb) is a relatively rare alkali metal and is most commonly found in nature in the form of minerals like lepidolite and feldspar. Rubidium is typically found in trace amounts within these minerals, and its natural occurrence is much less abundant compared to sodium or potassium.
26. Which of the following alkali metals is commonly found in mineral deposits in the Earth’s crust?
ⓐ. Lithium (Li)
ⓑ. Sodium (Na)
ⓒ. Potassium (K)
ⓓ. Rubidium (Rb)
Correct Answer: Potassium (K)
Explanation: Potassium (K) is widely distributed in the Earth’s crust and is commonly found in minerals such as potash (KCl) and sylvite (KCl), which are significant sources of potassium for industrial use. Potassium is also present in other silicate minerals but is most commonly extracted from potash deposits.
27. How does the occurrence of alkali metals in nature generally compare with their reactivity?
ⓐ. More reactive alkali metals are found in higher concentrations.
ⓑ. Less reactive alkali metals are found in higher concentrations.
ⓒ. The reactivity does not affect their occurrence.
ⓓ. Alkali metals do not occur naturally.
Correct Answer: Less reactive alkali metals are found in higher concentrations.
Explanation: Less reactive alkali metals, such as sodium and potassium, are found in higher concentrations in nature. The reactivity of alkali metals increases as we move down the group, but the more reactive metals like lithium and rubidium are less abundant. This is due to the fact that highly reactive elements tend to form compounds quickly and are not found in their free (metallic) state in nature.
28. Which natural occurrence of sodium is the primary source for producing sodium hydroxide (NaOH)?
ⓐ. Sodium bicarbonate
ⓑ. Sodium nitrate
ⓒ. Sodium sulfate
ⓓ. Sodium chloride
Correct Answer: Sodium chloride
Explanation: Sodium hydroxide (NaOH), also known as caustic soda, is primarily produced by the electrolysis of sodium chloride (NaCl), which is the most abundant source of sodium in nature. This process, known as the chlor-alkali process, is a key industrial method for producing sodium hydroxide, chlorine gas, and hydrogen gas.
29. What is the major natural source of potassium used in fertilizers?
ⓐ. Potash (KCl)
ⓑ. Sodium chloride (NaCl)
ⓒ. Potassium nitrate (KNO₃)
ⓓ. Potassium sulfate (K₂SO₄)
Correct Answer: Potash (KCl)
Explanation: Potash, primarily in the form of potassium chloride (KCl), is the most significant natural source of potassium used in fertilizers. Potassium is an essential nutrient for plant growth, and potash is mined from mineral deposits found in various parts of the world, particularly in Canada, Russia, and the United States.
30. How is rubidium typically obtained from nature?
ⓐ. By extracting it from seawater
ⓑ. From potassium-rich minerals
ⓒ. From lithium-rich ores
ⓓ. From rubidium-bearing minerals like lepidolite
Correct Answer: From rubidium-bearing minerals like lepidolite
Explanation: Rubidium is primarily obtained from rubidium-bearing minerals such as lepidolite and pollucite. These minerals contain trace amounts of rubidium, which is extracted through various mining and refining processes. Unlike sodium and potassium, rubidium is not found in large quantities and is relatively rare in nature.
31. Which of the following alkali metals is the softest?
ⓐ. Sodium (Na)
ⓑ. Lithium (Li)
ⓒ. Potassium (K)
ⓓ. Rubidium (Rb)
Correct Answer: Potassium (K)
Explanation: Potassium (K) is the softest alkali metal. It can be easily cut with a knife due to its low density and weak metallic bonding. As we move down Group 1, the alkali metals become progressively softer, with potassium being softer than sodium and lithium.
32. What is the density trend for alkali metals as we move down the group?
ⓐ. Density increases
ⓑ. Density decreases
ⓒ. Density remains the same
ⓓ. Density fluctuates
Correct Answer: Density fluctuates
Explanation: The density of alkali metals fluctuates; it increases from Li to Na, drops for K, and then increases for Rb and Cs due to an irregular relationship between increasing atomic mass and atomic volume.
33. Which alkali metal is the least conductive of electricity?
ⓐ. Lithium (Li)
ⓑ. Sodium (Na)
ⓒ. Potassium (K)
ⓓ. Rubidium (Rb)
Correct Answer: Lithium (Li)
Explanation: Lithium (Li) is the least conductive of electricity among the alkali metals. This is because lithium has the smallest atomic size, leading to more tightly held electrons and a lower ability to conduct electricity compared to the larger alkali metals.
34. What is the general trend of melting points in alkali metals?
ⓐ. Melting points increase as we move down the group.
ⓑ. Melting points decrease as we move down the group.
ⓒ. Melting points remain constant across the group.
ⓓ. Melting points fluctuate randomly.
Correct Answer: Melting points decrease as we move down the group.
Explanation: The melting points of alkali metals decrease as we move down Group 1. This is due to the weakening of metallic bonding as the atoms get larger, making it easier for the atoms to separate and change from solid to liquid. For example, lithium has the highest melting point, while cesium has the lowest.
35. Which of the following alkali metals can be cut easily with a knife due to its softness?
ⓐ. Sodium (Na)
ⓑ. Lithium (Li)
ⓒ. Potassium (K)
ⓓ. Rubidium (Rb)
Correct Answer: Sodium (Na)
Explanation: Sodium (Na) is a soft alkali metal that can be easily cut with a knife. Its softness increases as you move down the group, but sodium is still relatively soft compared to other metals. Potassium and rubidium are even softer than sodium.
36. Why do alkali metals have low densities?
ⓐ. They have large atomic masses.
ⓑ. They have tightly packed atoms.
ⓒ. They have large atomic radii and loosely packed atoms.
ⓓ. They are heavier than most metals.
Correct Answer: They have large atomic radii and loosely packed atoms.
Explanation: Alkali metals have low densities because they have large atomic radii and the atoms are not tightly packed. The weak metallic bonds between the atoms allow for a relatively low mass-to-volume ratio, resulting in low density, especially in the lighter alkali metals like lithium and sodium.
37. Which of the following alkali metals has the lowest melting point?
ⓐ. Sodium (Na)
ⓑ. Potassium (K)
ⓒ. Lithium (Li)
ⓓ. Cesium (Cs)
Correct Answer: Cesium (Cs)
Explanation: Cesium (Cs) has the lowest melting point of the alkali metals. As the size of the alkali metal atom increases, the metallic bonding becomes weaker, making it easier to melt. Cesium, being the largest alkali metal, has the weakest metallic bonds and the lowest melting point.
38. How does the electrical conductivity of alkali metals change as we move down Group 1?
ⓐ. Conductivity increases.
ⓑ. Conductivity decreases.
ⓒ. Conductivity remains the same.
ⓓ. Conductivity fluctuates.
Correct Answer: Conductivity increases.
Explanation: The electrical conductivity of alkali metals increases as we move down the group. This is because the outer electron becomes more loosely bound, making it easier for the electron to move and carry an electrical current. Potassium and rubidium, being larger atoms, have a higher conductivity than lithium and sodium.
39. Which of the following alkali metals is most commonly used in the production of liquid metal coolants for nuclear reactors due to its low melting point and high conductivity?
ⓐ. Lithium (Li)
ⓑ. Cesium (Cs)
ⓒ. Potassium (K)
ⓓ. Sodium (Na)
Correct Answer: Sodium (Na)
Explanation: Sodium (Na) is commonly used in the production of liquid metal coolants for nuclear reactors because of its low melting point, good thermal conductivity, and relatively low cost. It remains in a liquid state at reactor operating temperatures and efficiently transfers heat away from the reactor core.
40. Which of the following is true about the physical properties of alkali metals?
ⓐ. They are hard, dense, and have high melting points.
ⓑ. They are soft, have low density, and low melting points.
ⓒ. They are soft, have high density, and high melting points.
ⓓ. They are hard, have low density, and high melting points.
Correct Answer: They are soft, have low density, and low melting points.
Explanation: Alkali metals are soft and have low densities due to their large atomic sizes and weak metallic bonding. As we move down the group, the softness increases, and the melting points decrease. These metals are characterized by their low melting points compared to most other metals.
41. What is the trend in ionization enthalpy as we move down Group 1 (Alkali Metals)?
ⓐ. Ionization enthalpy increases
ⓑ. Ionization enthalpy decreases
ⓒ. Ionization enthalpy remains constant
ⓓ. Ionization enthalpy fluctuates
Correct Answer: Ionization enthalpy decreases
Explanation: As we move down Group 1, the ionization enthalpy decreases. This is because the atomic size increases, and the outermost electron is farther from the nucleus, making it easier to remove. As a result, less energy is required to ionize the atom.
42. Which alkali metal has the highest ionization enthalpy?
ⓐ. Lithium (Li)
ⓑ. Sodium (Na)
ⓒ. Potassium (K)
ⓓ. Rubidium (Rb)
Correct Answer: Lithium (Li)
Explanation: Lithium (Li) has the highest ionization enthalpy among the alkali metals. This is because it is the smallest alkali metal, and its outermost electron is more tightly bound to the nucleus compared to the other alkali metals, making it harder to remove.
43. How does the reactivity of alkali metals change as we move down Group 1?
ⓐ. Reactivity decreases
ⓑ. Reactivity remains the same
ⓒ. Reactivity increases
ⓓ. Reactivity fluctuates
Correct Answer: Reactivity increases
Explanation: As we move down Group 1, the reactivity of alkali metals increases. This is due to the increasing atomic size, which makes the outermost electron easier to remove. The greater the size, the weaker the attraction between the nucleus and the outermost electron, leading to higher reactivity.
44. What happens to the atomic radius of alkali metals as we move down Group 1?
ⓐ. Atomic radius decreases
ⓑ. Atomic radius fluctuates
ⓒ. Atomic radius remains constant
ⓓ. Atomic radius increases
Correct Answer: Atomic radius increases
Explanation: As we move down Group 1, the atomic radius increases. This is due to the addition of electron shells as we move to heavier alkali metals. The increased number of shells causes the atoms to become larger, despite the increase in nuclear charge.
45. How does the melting point of alkali metals change as we move down Group 1?
ⓐ. Melting point increases
ⓑ. Melting point decreases
ⓒ. Melting point remains the same
ⓓ. Melting point fluctuates
Correct Answer: Melting point decreases
Explanation: The melting point of alkali metals decreases as we move down Group 1. This is due to the weakening of metallic bonds as the atomic size increases. The outermost electron becomes more loosely bound, making it easier for the metal to melt.
46. What happens to the density of alkali metals as we move down Group 1?
ⓐ. Density increases
ⓑ. Density decreases
ⓒ. Density remains constant
ⓓ. Density fluctuates
Correct Answer: Density fluctuates
Explanation: The density of alkali metals fluctuates; it increases from Li to Na, drops for K (making it less dense than Na), and then increases again for Rb and Cs.
47. Which alkali metal is the most reactive with water?
ⓐ. Lithium (Li)
ⓑ. Sodium (Na)
ⓒ. Potassium (K)
ⓓ. Cesium (Cs)
Correct Answer: Cesium (Cs)
Explanation: Cesium (Cs) is the most reactive alkali metal with water. As the atomic size increases, the reactivity increases because the outer electron becomes more easily removed. Cesium, being the largest alkali metal, reacts vigorously with water, more so than lithium, sodium, and potassium.
48. What is the trend in the hydration enthalpy of alkali metals as we move down Group 1?
ⓐ. Hydration enthalpy increases
ⓑ. Hydration enthalpy decreases
ⓒ. Hydration enthalpy remains the same
ⓓ. Hydration enthalpy fluctuates
Correct Answer: Hydration enthalpy decreases
Explanation: Hydration enthalpy decreases as we move down Group 1. This is because the ionic size increases, and the larger the ion, the weaker the attraction between the ion and water molecules, leading to a lower amount of heat released during hydration.
49. Which of the following is the correct trend for the solubility of alkali metal compounds in water?
ⓐ. Solubility increases as we move down the group
ⓑ. Solubility decreases as we move down the group
ⓒ. Solubility remains constant across the group
ⓓ. Solubility fluctuates
Correct Answer: Solubility increases as we move down the group
Explanation: The solubility of alkali metal compounds, especially halides, increases as we move down Group 1. This trend is due to the decreasing lattice energy as the ionic size increases, making it easier for the compounds to dissolve in water.
50. Which of the following statements is true for the alkali metals’ behavior in terms of their conductivity as we move down the group?
ⓐ. Conductivity decreases
ⓑ. Conductivity remains the same
ⓒ. Conductivity increases
ⓓ. Conductivity fluctuates
Correct Answer: Conductivity increases
Explanation: As we move down Group 1, the electrical conductivity of alkali metals increases. This is due to the outer electron becoming more loosely bound, allowing for easier flow of electrons, which leads to better conductivity, especially in heavier alkali metals like rubidium and cesium.
51. Why does reactivity increase as we move down Group 1 (Alkali Metals)?
ⓐ. The atomic size decreases
ⓑ. The ionization enthalpy increases
ⓒ. The atomic size increases, and ionization enthalpy decreases
ⓓ. The density decreases
Correct Answer: The atomic size increases, and ionization enthalpy decreases
Explanation: As we move down Group 1, the atomic size increases, which makes the outermost electron more loosely held. This leads to a decrease in ionization enthalpy, making it easier to remove the outer electron. As a result, the reactivity of alkali metals increases as we move down the group.
52. Which of the following alkali metals is the most reactive with water?
ⓐ. Lithium (Li)
ⓑ. Sodium (Na)
ⓒ. Potassium (K)
ⓓ. Cesium (Cs)
Correct Answer: Cesium (Cs)
Explanation: Cesium (Cs) is the most reactive alkali metal with water. As the atomic size increases down the group, the outer electron is more easily lost, which enhances the metal’s reactivity. Cesium reacts violently with water, more so than lithium, sodium, and potassium.
53. Which of the following alkali metals reacts most vigorously with oxygen?
ⓐ. Lithium (Li)
ⓑ. Sodium (Na)
ⓒ. Potassium (K)
ⓓ. Rubidium (Rb)
Correct Answer: Rubidium (Rb)
Explanation: As we move down Group 1, alkali metals become increasingly reactive with oxygen. Rubidium (Rb) is more reactive with oxygen than lithium (Li), sodium (Na), and potassium (K) due to its larger atomic size, which leads to weaker attraction between the outermost electron and the nucleus.
54. How does the ease of forming metal hydroxides change as we move down Group 1?
ⓐ. It decreases
ⓑ. It increases
ⓒ. It remains constant
ⓓ. It fluctuates
Correct Answer: It increases
Explanation: As we move down Group 1, alkali metals become more reactive with water, leading to an easier formation of metal hydroxides. The reactivity of alkali metals with water increases as the atomic size increases and the ionization enthalpy decreases, making the formation of hydroxides faster.
55. Which of the following reactions best demonstrates the increasing reactivity of alkali metals with water down the group?
ⓐ. $Na + H_2O \rightarrow NaOH + H_2$
ⓑ. $K + H_2O \rightarrow KOH + H_2$
ⓒ. $Li + H_2O \rightarrow LiOH + H_2$
ⓓ. $Cs + H_2O \rightarrow CsOH + H_2$
Correct Answer: $Cs + H_2O \rightarrow CsOH + H_2$
Explanation: Cesium (Cs) reacts the most vigorously with water among the alkali metals. This reaction produces cesium hydroxide (CsOH) and hydrogen gas (H₂), and is highly exothermic, often resulting in flames and explosions.
56. Which alkali metal would likely react the least violently with water?
ⓐ. Lithium (Li)
ⓑ. Sodium (Na)
ⓒ. Potassium (K)
ⓓ. Cesium (Cs)
Correct Answer: Lithium (Li)
Explanation: Lithium (Li) is the least reactive alkali metal with water compared to sodium, potassium, and cesium. The smaller atomic size of lithium means that its outer electron is more tightly held, making it less reactive than the other alkali metals.
57. Which of the following explains why potassium (K) is more reactive than sodium (Na)?
ⓐ. Potassium has a smaller atomic size
ⓑ. Potassium has a higher ionization energy
ⓒ. Potassium has a lower ionization energy and larger atomic size
ⓓ. Potassium has a stronger metallic bond
Correct Answer: Potassium has a lower ionization energy and larger atomic size
Explanation: Potassium (K) is more reactive than sodium (Na) because it has a lower ionization energy and a larger atomic size. The larger atomic radius makes the outer electron easier to remove, increasing its reactivity.
58. What is the reactivity trend for alkali metals with halogens as we move down the group?
ⓐ. Reactivity decreases
ⓑ. Reactivity increases
ⓒ. Reactivity remains constant
ⓓ. Reactivity fluctuates
Correct Answer: Reactivity increases
Explanation: As we move down Group 1, alkali metals become more reactive with halogens. This is due to the larger atomic size and the easier removal of the outer electron, which makes the alkali metal more likely to react and form ionic compounds with halogens.
59. Which alkali metal reacts most vigorously with halogens to form halides?
ⓐ. Lithium (Li)
ⓑ. Sodium (Na)
ⓒ. Potassium (K)
ⓓ. Cesium (Cs)
Correct Answer: Cesium (Cs)
Explanation: Cesium (Cs) reacts most vigorously with halogens to form halides, such as cesium chloride (CsCl). As the size of alkali metals increases down the group, the outermost electron is more easily lost, resulting in stronger reactions with halogens.
60. Which factor most directly influences the increasing reactivity of alkali metals as we move down the group?
ⓐ. Increasing ionization energy
ⓑ. Decreasing ionization energy
ⓒ. Decreasing atomic radius
ⓓ. Increasing electron affinity
Correct Answer: Decreasing ionization energy
Explanation: The increasing reactivity of alkali metals as we move down Group 1 is mainly due to the decreasing ionization energy. As the atomic size increases, the outermost electron is more loosely bound to the nucleus, making it easier for the metal to lose the electron and react.
61. What is the electronic configuration of calcium (Ca)?
ⓐ. $[Ne], 3s^2$
ⓑ. $[Ne], 3s^2, 3p^6$
ⓒ. $[Kr], 5s^2$
ⓓ. $[Ar], 4s^2$
Correct Answer: $[Ar], 4s^2$
Explanation: Calcium (Ca) belongs to Group 2 of the periodic table (alkaline earth metals). Its atomic number is 20, and its electronic configuration is $[Ar], 4s^2$, meaning it has two electrons in the $4s$ orbital.
62. What is the common feature of all alkaline earth metals (Group 2) in terms of their electronic configuration?
ⓐ. They all have a completely filled $p$ orbital.
ⓑ. They all have two electrons in their outermost $s$ orbital.
ⓒ. They all have a full $d$ orbital.
ⓓ. They all have one electron in their outermost shell.
Correct Answer: They all have two electrons in their outermost $s$ orbital.
Explanation: All alkaline earth metals (Group 2) share the characteristic of having two electrons in their outermost $s$ orbital. This gives them the $ns^2$ configuration, which contributes to their chemical properties, such as forming ionic compounds with a +2 charge.
63. Which of the following elements has the electronic configuration $[Ne], 3s^2, 3p^6, 4s^2$?
ⓐ. Magnesium (Mg)
ⓑ. Barium (Ba)
ⓒ. Calcium (Ca)
ⓓ. Strontium (Sr)
Correct Answer: Calcium (Ca)
Explanation: Calcium (Ca) has the atomic number 20, and its electronic configuration is $[Ar], 4s^2$, but the representation $[Ne], 3s^2, 3p^6, 4s^2$ is also commonly used to describe its structure when considering only the outer shell configuration.
64. What is the general trend of ionization energy as we move down Group 2 (Alkaline Earth Metals)?
ⓐ. Ionization energy increases
ⓑ. Ionization energy decreases
ⓒ. Ionization energy remains constant
ⓓ. Ionization energy fluctuates
Correct Answer: Ionization energy decreases
Explanation: As we move down Group 2, the ionization energy decreases. This is due to the increasing atomic size and the fact that the outermost electrons are farther from the nucleus, making them easier to remove. The lower ionization energy contributes to the reactivity of the alkaline earth metals.
65. Which of the following elements is an alkaline earth metal with the electron configuration $[Kr], 5s^2$?
ⓐ. Magnesium (Mg)
ⓑ. Calcium (Ca)
ⓒ. Barium (Ba)
ⓓ. Strontium (Sr)
Correct Answer: Strontium (Sr)
Explanation: Strontium (Sr) is an alkaline earth metal with the atomic number 38. Its configuration is $[Kr], 5s^2$, as it has the 36 electrons of Krypton plus two valence electrons in the 5s orbital.
66. Which of the following elements has the electronic configuration $[Ne], 3s^2$?
ⓐ. Magnesium (Mg)
ⓑ. Calcium (Ca)
ⓒ. Strontium (Sr)
ⓓ. Barium (Ba)
Correct Answer: Magnesium (Mg)
Explanation: Magnesium (Mg) belongs to Group 2, with the atomic number 12. Its electronic configuration is $[Ne], 3s^2$, indicating that it has two electrons in the outermost $s$ orbital.
67. What is the electronic configuration of beryllium (Be)?
ⓐ. $[Kr], 5s^2$
ⓑ. $[Ne], 3s^2$
ⓒ. $[Ar], 4s^2$
ⓓ. $[He], 2s^2$
Correct Answer: $[He], 2s^2$
Explanation: Beryllium (Be) is an alkaline earth metal with the atomic number 4. Its electronic configuration is $[He], 2s^2$, meaning it has two electrons in the $2s$ orbital. It is the lightest member of the alkaline earth metals.
68. How does the reactivity of alkaline earth metals change as we move down the group?
ⓐ. Reactivity increases
ⓑ. Reactivity decreases
ⓒ. Reactivity remains the same
ⓓ. Reactivity fluctuates
Correct Answer: Reactivity increases
Explanation: As we move down Group 2, the reactivity of alkaline earth metals increases. This is due to the decreasing ionization energy and increasing atomic size, which makes it easier for these elements to lose their outermost electrons, leading to increased reactivity.
69. Which of the following compounds is commonly formed by alkaline earth metals?
ⓐ. Chlorides with a +1 charge
ⓑ. Chlorides with a +2 charge
ⓒ. Oxides with a +2 charge
ⓓ. Oxides with a -1 charge
Correct Answer: Oxides with a +2 charge
Explanation: Alkaline earth metals form oxides with a +2 charge. These elements, with the electron configuration $ns^2$, lose both electrons in their outermost shell to form divalent cations ($M^{2+}$), which combine with oxygen to form metal oxides such as $MgO$ (magnesium oxide) and $CaO$ (calcium oxide).
70. What is the electronic configuration of strontium (Sr)?
ⓐ. $[Kr], 5s^2$
ⓑ. $[Xe], 6s^2$
ⓒ. $[Ar], 4s^2$
ⓓ. $[Kr], 4d^{10}, 5s^2$
Correct Answer: $[Kr], 5s^2$
Explanation: Strontium (Sr) is an alkaline earth metal with atomic number 38, placing it in Period 5. Its configuration is $[Kr], 5s^2$, representing the Krypton core and two valence electrons in the 5s orbital.
71. Which of the following is a natural ore of calcium?
ⓐ. Dolomite
ⓑ. Gypsum
ⓒ. Limestone
ⓓ. All of the above
Correct Answer: All of the above
Explanation: Dolomite, gypsum, and limestone are all natural ores of calcium. Dolomite ($CaMg(CO_3)_2$) contains both calcium and magnesium, gypsum ($CaSO_4\cdot 2H_2O$) is a sulfate mineral of calcium, and limestone ($CaCO_3$) is primarily made up of calcium carbonate. All these minerals are significant sources of calcium in nature.
72. Where is dolomite commonly found in nature?
ⓐ. In igneous rocks
ⓑ. In metamorphic rocks
ⓒ. In sedimentary rocks
ⓓ. In volcanic ash
Correct Answer: In sedimentary rocks
Explanation: Dolomite is commonly found in sedimentary rocks. It is formed from the alteration of limestone and is often associated with other carbonate minerals. The presence of dolomite in sedimentary rocks indicates the former presence of calcium and magnesium-rich water.
73. Which of the following is the chemical formula of gypsum?
ⓐ. $CaCO_3$
ⓑ. $CaSO_4 \cdot 2H_2O$
ⓒ. $CaMg(CO_3)_2$
ⓓ. $Ca(OH)_2$
Correct Answer: $CaSO_4 \cdot 2H_2O$
Explanation: The chemical formula of gypsum is $CaSO_4 \cdot 2H_2O$, which consists of calcium sulfate with two water molecules of crystallization. Gypsum is commonly used in the production of plaster and as a fertilizer.
74. Which mineral is primarily composed of calcium carbonate and is commonly used in construction?
ⓐ. Dolomite
ⓑ. Gypsum
ⓒ. Limestone
ⓓ. Chalk
Correct Answer: Limestone
Explanation: Limestone is primarily composed of calcium carbonate ($CaCO_3$) and is widely used in construction for making cement and as a building material. It is a common sedimentary rock that forms from the accumulation of shells, corals, and marine organisms.
75. What is the main industrial use of dolomite?
ⓐ. As a source of magnesium
ⓑ. For making plaster
ⓒ. For fertilizer production
ⓓ. As a building material
Correct Answer: As a source of magnesium
Explanation: Dolomite ($CaMg(CO_3)_2$) is primarily used as a source of magnesium, which is extracted for use in various industrial applications. It is also used in the manufacture of refractory materials and as a flux in steelmaking.
76. Which of the following reactions occurs when limestone (CaCO₃) is heated?
ⓐ. $CaCO_3 \xrightarrow{heat} CaO + CO_2$
ⓑ. $CaCO_3 \xrightarrow{heat} CaSO_4 + CO_2$
ⓒ. $CaCO_3 \xrightarrow{heat} CaO + O_2$
ⓓ. $CaCO_3 + H_2O \rightarrow Ca(OH)_2$
Correct Answer: $CaCO_3 \xrightarrow{heat} CaO + CO_2$
Explanation: When limestone ($CaCO_3$) is heated, it undergoes thermal decomposition to form calcium oxide ($CaO$) and carbon dioxide ($CO_2$). This reaction is essential in the production of quicklime, which is used in various industrial processes.
77. Which of the following alkaline earth metals is commonly found in the mineral gypsum?
ⓐ. Magnesium
ⓑ. Strontium
ⓒ. Barium
ⓓ. Calcium
Correct Answer: Calcium
Explanation: Calcium is the alkaline earth metal commonly found in gypsum, which is a hydrated calcium sulfate ($CaSO_4 \cdot 2H_2O$). Gypsum is used in the production of plaster and as a fertilizer, and it is an important natural source of calcium.
78. Where is limestone predominantly found?
ⓐ. In volcanic regions
ⓑ. In marine sedimentary environments
ⓒ. In mountainous regions
ⓓ. In polar ice caps
Correct Answer: In marine sedimentary environments
Explanation: Limestone is predominantly found in marine sedimentary environments. It forms from the accumulation of marine organisms, such as corals and shells, that are rich in calcium carbonate ($CaCO_3$). It is commonly found in shallow, warm marine environments.
79. What is the main component of dolomite?
ⓐ. Calcium carbonate
ⓑ. Calcium magnesium carbonate
ⓒ. Magnesium sulfate
ⓓ. Calcium sulfate
Correct Answer: Calcium magnesium carbonate
Explanation: Dolomite is primarily composed of calcium magnesium carbonate ($CaMg(CO_3)_2$). It is a sedimentary rock that forms from the alteration of limestone and is an important mineral in the production of magnesium.
80. Which mineral is a significant source of lime (calcium oxide, CaO) in the industry?
ⓐ. Gypsum
ⓑ. Dolomite
ⓒ. Limestone
ⓓ. Chalk
Correct Answer: Limestone
Explanation: Limestone ($CaCO_3$) is the primary source of lime (calcium oxide, $CaO$) in the industry. When heated, limestone decomposes to form calcium oxide and carbon dioxide, which is used in various applications such as in cement manufacturing, steel production, and water treatment.
81. How do the physical properties of alkaline earth metals compare to alkali metals?
ⓐ. Alkaline earth metals are softer and have lower melting points
ⓑ. Alkaline earth metals are more reactive and have lower melting points
ⓒ. Alkaline earth metals are less reactive and have similar densities
ⓓ. Alkaline earth metals are harder and have higher melting points
Correct Answer: Alkaline earth metals are harder and have higher melting points
Explanation: Alkaline earth metals are harder and have higher melting points than alkali metals. This is due to the stronger metallic bonds formed by the two electrons in the outermost $s$ orbital, compared to the single outer electron in alkali metals. As a result, alkaline earth metals are more stable and less reactive.
82. Which of the following is true regarding the reactivity of alkaline earth metals compared to alkali metals?
ⓐ. Alkaline earth metals are more reactive than alkali metals
ⓑ. Alkaline earth metals are less reactive than alkali metals
ⓒ. Both alkaline earth metals and alkali metals have similar reactivity
ⓓ. Alkaline earth metals and alkali metals do not react with water
Correct Answer: Alkaline earth metals are less reactive than alkali metals
Explanation: Alkaline earth metals are less reactive than alkali metals. While both groups are highly reactive, alkali metals are more reactive because they have one electron in their outermost shell, which is more easily lost compared to the two electrons in the outer shell of alkaline earth metals.
83. Which of the following alkaline earth metals has the highest melting point?
ⓐ. Magnesium (Mg)
ⓑ. Calcium (Ca)
ⓒ. Barium (Ba)
ⓓ. Strontium (Sr)
Correct Answer: Magnesium (Mg)
Explanation: Magnesium (Mg) has the highest melting point among the alkaline earth metals. This is due to its relatively small atomic size and stronger metallic bonding. Smaller atoms lead to stronger bonds and thus higher melting points compared to larger atoms like calcium, barium, and strontium.
84. How does the hardness of alkaline earth metals change as we move down the group?
ⓐ. Hardness increases
ⓑ. Hardness remains constant
ⓒ. Hardness decreases
ⓓ. Hardness fluctuates
Correct Answer: Hardness decreases
Explanation: As we move down Group 2, the hardness of alkaline earth metals decreases. This is because the atoms get larger, and the metallic bonds become weaker. Larger atoms result in less tightly held electrons, reducing the strength of the metallic lattice and making the metal softer.
85. Which of the following alkaline earth metals is the hardest?
ⓐ. Magnesium (Mg)
ⓑ. Calcium (Ca)
ⓒ. Barium (Ba)
ⓓ. Strontium (Sr)
Correct Answer: Magnesium (Mg)
Explanation: Magnesium (Mg) is the hardest among the alkaline earth metals. Its smaller atomic size compared to the other alkaline earth metals results in stronger metallic bonds and greater hardness. Barium and strontium, being larger atoms, are softer in comparison.
86. Which of the following factors contributes to the higher melting points of alkaline earth metals compared to alkali metals?
ⓐ. Stronger metallic bonding due to two valence electrons
ⓑ. Larger atomic size
ⓒ. More ionization energy
ⓓ. Weaker bonds in the lattice structure
Correct Answer: Stronger metallic bonding due to two valence electrons
Explanation: Alkaline earth metals have stronger metallic bonding compared to alkali metals due to having two electrons in the outermost $s$ orbital. This results in stronger bonds between atoms and higher melting points. Alkali metals, with only one electron in their outermost shell, form weaker metallic bonds.
87. Which of the following alkaline earth metals is the least reactive with water?
ⓐ. Magnesium (Mg)
ⓑ. Calcium (Ca)
ⓒ. Barium (Ba)
ⓓ. Strontium (Sr)
Correct Answer: Magnesium (Mg)
Explanation: Magnesium (Mg) is the least reactive alkaline earth metal with water. Although magnesium reacts with water, the reaction is less vigorous compared to calcium, strontium, and barium. The increased atomic size and lower ionization energy of the heavier metals make them more reactive with water.
88. How does the conductivity of alkaline earth metals compare to alkali metals?
ⓐ. Alkaline earth metals are better conductors of electricity
ⓑ. Neither is a good conductor of electricity
ⓒ. Both have similar conductivity
ⓓ. Alkali metals are better conductors of electricity
Correct Answer: Alkali metals are better conductors of electricity
Explanation: Alkali metals are better conductors of electricity compared to alkaline earth metals. This is due to their single valence electron, which is more easily delocalized and able to move freely in the metal lattice, allowing better electrical conductivity. Alkaline earth metals have two valence electrons, making them slightly less conductive.
89. What is the trend in the ionization energy of alkaline earth metals as we move down the group?
ⓐ. Ionization energy increases
ⓑ. Ionization energy decreases
ⓒ. Ionization energy remains constant
ⓓ. Ionization energy fluctuates
Correct Answer: Ionization energy decreases
Explanation: As we move down Group 2, the ionization energy of alkaline earth metals decreases. This is because the atomic size increases, and the outer electrons are farther from the nucleus, making them easier to remove. The decreased ionization energy contributes to the increasing reactivity of the elements as we go down the group.
90. Which of the following alkaline earth metals has the lowest melting point?
ⓐ. Magnesium (Mg)
ⓑ. Calcium (Ca)
ⓒ. Barium (Ba)
ⓓ. Strontium (Sr)
Correct Answer: Magnesium (Mg)
Explanation: Magnesium (Mg) has the lowest melting point (650°C) among the options provided (Ca, Sr, Ba); the melting point trend in Group 2 is irregular and does not simply decrease.
91. What happens to the atomic radius of alkaline earth metals as we move down Group 2?
ⓐ. Atomic radius decreases
ⓑ. Atomic radius increases
ⓒ. Atomic radius remains the same
ⓓ. Atomic radius fluctuates
Correct Answer: Atomic radius increases
Explanation: As we move down Group 2, the atomic radius increases. This is due to the addition of electron shells, which causes the atoms to become larger. Despite the increase in nuclear charge, the added shells cause a greater shielding effect, making the outermost electrons more distant from the nucleus.
92. How does the reactivity of alkaline earth metals change as we move down Group 2?
ⓐ. Reactivity decreases
ⓑ. Reactivity remains the same
ⓒ. Reactivity increases
ⓓ. Reactivity fluctuates
Correct Answer: Reactivity increases
Explanation: The reactivity of alkaline earth metals increases as we move down the group. This is because the ionization energy decreases, making it easier for the metals to lose their two outermost electrons. The larger atomic size also contributes to increased reactivity, especially with water and halogens.
93. Which of the following properties increases as we move down Group 2?
ⓐ. Ionization energy
ⓑ. Electronegativity
ⓒ. Atomic size
ⓓ. Melting point
Correct Answer: Atomic size
Explanation: As we move down Group 2, the atomic size increases due to the addition of electron shells. This causes a larger distance between the nucleus and the outermost electrons, making the atomic radius larger as we move to heavier elements like barium and radium.
94. What is the trend in ionization energy as we move down Group 2?
ⓐ. Ionization energy increases
ⓑ. Ionization energy fluctuates
ⓒ. Ionization energy remains constant
ⓓ. Ionization energy decreases
Correct Answer: Ionization energy decreases
Explanation: Ionization energy decreases as we move down Group 2. This occurs because the atomic size increases, and the outermost electrons are farther from the nucleus. The larger atomic size results in less attraction between the nucleus and the outermost electrons, making it easier to remove these electrons.
95. How does the solubility of alkaline earth metal hydroxides change as we move down the group?
ⓐ. Solubility increases
ⓑ. Solubility decreases
ⓒ. Solubility remains the same
ⓓ. Solubility fluctuates
Correct Answer: Solubility increases
Explanation: As we move down Group 2, the solubility of alkaline earth metal hydroxides increases. For example, while magnesium hydroxide ($Mg(OH)_2$) is only slightly soluble in water, calcium hydroxide ($Ca(OH)_2$) is more soluble, and barium hydroxide ($Ba(OH)_2$) is quite soluble. This trend is due to the decreasing lattice energy as the atomic size increases.
96. What happens to the electronegativity of alkaline earth metals as we move down Group 2?
ⓐ. Electronegativity increases
ⓑ. Electronegativity fluctuates
ⓒ. Electronegativity remains constant
ⓓ. Electronegativity decreases
Correct Answer: Electronegativity decreases
Explanation: Electronegativity decreases as we move down Group 2. This is because the atomic size increases, and the ability of the nucleus to attract bonding electrons weakens. Larger atoms have more shielding from inner electrons, which reduces their effective nuclear charge and thus decreases electronegativity.
97. What happens to the melting points of alkaline earth metals as we move down Group 2?
ⓐ. Melting point increases
ⓑ. Melting point decreases
ⓒ. Melting point remains the same
ⓓ. Melting point fluctuates
Correct Answer: Melting point decreases
Explanation: As we move down Group 2, the melting points of alkaline earth metals generally decrease. This is because the atomic size increases, and the metallic bonds become weaker, making it easier for the atoms to separate and melt. For example, magnesium has a higher melting point than barium.
98. Which of the following alkaline earth metals has the lowest density?
ⓐ. Magnesium (Mg)
ⓑ. Calcium (Ca)
ⓒ. Barium (Ba)
ⓓ. Strontium (Sr)
Correct Answer: Calcium (Ca)
Explanation: Calcium (Ca) has the lowest density (1.55 g/cm³); this is a known exception to the general trend, as Magnesium (1.74 g/cm³) is denser.
99. How does the reactivity of alkaline earth metals with halogens change as we move down the group?
ⓐ. Reactivity decreases
ⓑ. Reactivity remains the same
ⓒ. Reactivity increases
ⓓ. Reactivity fluctuates
Correct Answer: Reactivity increases
Explanation: As we move down Group 2, the reactivity of alkaline earth metals with halogens increases. This is because the outermost electrons are more easily lost due to the decreasing ionization energy and increasing atomic size. As a result, these metals readily form ionic halides with halogens, such as $CaCl_2$ and $BaI_2$.
100. Which of the following alkaline earth metals is the least reactive with water?
ⓐ. Magnesium (Mg)
ⓑ. Calcium (Ca)
ⓒ. Strontium (Sr)
ⓓ. Barium (Ba)
Correct Answer: Magnesium (Mg)
Explanation: Magnesium (Mg) is the least reactive alkaline earth metal with water. While it does react with water, the reaction is slow and requires steam for a more vigorous reaction. In contrast, calcium, strontium, and barium react much more readily with water.
Welcome to Class 11 Chemistry MCQs – Chapter 10: The s-Block Elements (Part 1). The s-block elements are a fundamental topic in NCERT/CBSE Class 11 Chemistry that forms the basis for understanding chemical reactivity and periodic trends. This chapter provides a comprehensive study of the alkali metals (Group 1) and alkaline earth metals (Group 2), their properties, compounds, and applications. With 359 MCQs divided into 4 parts, this chapter will guide you through detailed theory and practical applications that often appear in board exams, JEE, and NEET.
What you will learn & practice (Chapter 10: The s-Block Elements): In this part, we focus on the essential properties and trends of the s-block elements, their atomic structure, and their reactions with oxygen, water, and acids. You’ll dive into the detailed study of alkali metals (Li, Na, K, Rb, Cs, Fr) and alkaline earth metals (Be, Mg, Ca, Sr, Ba, Ra). Key topics include:
Topics covered in Part 1 (100 MCQs)
- General properties of s-block elements: Trends in atomic radius, ionization enthalpy, electronegativity, and atomic number
- Alkali metals (Group 1) – reactivity, trends in melting points, boiling points, solubility, and flame colors
- Alkaline earth metals (Group 2) – trends in reactivity, metallic character, and basicity of oxides
- Reactions of alkali and alkaline earth metals with water, oxygen, halogens, and acids
- Hydration energy and its role in solubility and ionic compounds
- Compounds of alkali metals: Sodium hydroxide, sodium carbonate, sodium bicarbonate, and their uses in industry
- Compounds of alkaline earth metals: Magnesium hydroxide, calcium oxide, and their importance in chemical industries
- Application of s-block elements in daily life, including in batteries, medicines, and environmental chemistry
- Occurrence and extraction of alkali and alkaline earth metals in nature, ores, and methods of isolation
How to use this site to master s-Block Elements MCQs
- Warm-up (10 mins): Review the topics listed above. Familiarize yourself with the key trends in s-block elements.
- Active practice: Solve 10–20 MCQs at a time. Click the option to see immediate feedback with correct answers and explanations.
- Build your personal deck: Use the ❤️ Heart on any MCQ to mark it as a Favourite. This will help you review essential topics later. Toggle the Favourite list for focused revision.
- Write it your way: Use the Workspace feature to jot down important notes or tricks for tricky questions. Your notes will auto-save for easy access anytime.
- Shuffle & strengthen: Use the Random button to prevent pattern memorization and test true understanding.
- Smart revision plan: Revisit your Favourite list on Day 2, Day 4, and Day 7 for spaced repetition. Review your Workspace notes the day before the exam for quick final prep.
Why this helps for Boards, JEE Main & NEET
- Boards: Conceptual clarity on reactivity trends and applications of s-block compounds is essential for exam success.
- JEE Main/Advanced: Numerical problems and reasoning on trends in atomic properties and applications of alkali metals often appear.
- NEET: Conceptual questions on the reactions of alkali and alkaline earth metals and their compounds are frequent in the exam.
- Your edge: Using Favourite and Workspace features to organize key topics and make your study sessions more efficient.
Common mistakes to avoid
- Forgetting trends: Electronegativity, ionization energy, and atomic radius show distinct patterns across groups.
- Mixing up the reactivity of alkali metals with alkaline earth metals; remember alkali metals are more reactive with water.
- Ignoring the importance of hydration energy when discussing solubility and lattice formation in ionic compounds.
- Confusing flame colors of alkali metals—each element produces a unique flame color in the presence of heat.
Use the ❤️ Heart to mark your favourite questions and go back to them for further practice. The Workspace allows you to take personalized notes that will stay safe and organized for future reviews. This method helps you focus on your weak areas and improve steadily.
Explore more: Class 11 Chemistry – Chapter Index, Class 11 – Subject Index, All Classes – MCQ Library.
Quick FAQ
Are s-block elements easy to understand?
Yes! Once you grasp the basic trends and properties, it becomes easier. Use MCQs to solidify your understanding.
How many MCQs should I solve per day?
Start with 20–30 MCQs. Focus on understanding the key concepts and then gradually increase the number.
How should I revise this chapter before the exam?
Use the Favourite Toggle to filter your marked questions and revise them. Also, check your Workspace notes for important formulas.
- 👉 Total MCQs in this chapter: 359 (100 + 100 + 100 + 59)
- 👉 This page: First 100 MCQs with answers & explanations
- 👉 Next: Move to Part 2 for the next 100 MCQs
FAQs on The s-Block Elements ▼
▸ What are The s-Block Elements MCQs in Class 11 Chemistry?
These are multiple-choice questions from Chapter 10 of NCERT Class 11 Chemistry – The s-Block Elements. They test your knowledge of the properties, reactivity, and uses of alkali metals and alkaline earth metals, along with their compounds.
▸ How many MCQs are available in this chapter?
There are a total of 359 MCQs from The s-Block Elements. They are divided into 4 structured parts – four sets of 100 questions each, with one set of 59 questions.
▸ Are The s-Block Elements MCQs important for JEE and NEET?
Yes, this chapter is very important for JEE and NEET exams. Key topics like the general properties of alkali and alkaline earth metals, their reactions with water, acids, and oxygen, and their compounds are frequently tested.
▸ Do these MCQs include correct answers and explanations?
Yes, each MCQ is accompanied by the correct answer and a detailed explanation, which helps students understand the reasoning behind the answers and build a deeper understanding of the concepts.
▸ Which subtopics are covered in these The s-Block Elements MCQs?
These MCQs cover subtopics such as the properties of alkali metals (Li, Na, K, etc.), their trends in the periodic table, the formation of ionic compounds, reactions with halogens and oxygen, the concept of hydration energy, and the chemical properties of alkaline earth metals (Be, Mg, Ca, etc.).