Class 11 Chemistry — Chapter 2: Structure of Atom Online Test

1. For hydrogen atom, the ratio of radii of 1st and 3rd orbit is:

2. The number of radial nodes in 5d orbital is:

3. The ionization energy of hydrogen atom in the ground state is:

4. The electronic configuration of neon (Z=10) is:

5. The electronic configuration of helium (Z=2) is:

6. Why do electrons prefer to occupy different orbitals of equal energy before pairing?

7. When two subshells have the same value, the one that fills first is the one with:

8. Which d-orbitals have lobes oriented between the axes (at 45° angles)?

9. The radial probability distribution curve of a 2s orbital shows:

10. The value of is associated with:

11. The azimuthal quantum number primarily determines the:

12. If , how many orbitals are possible in that shell?

13. The three dumbbell-shaped orbitals oriented along x, y, and z axes are:

14. What physical meaning does the wave function itself have?

15. The first line of the Brackett series corresponds to which transition?

16. Which equation represents Einstein’s photoelectric effect?

17. What is the wavelength of a radio wave with frequency ?

18. Which of the following is a correct postulate of Bohr’s atomic model?

19. In Chadwick’s experiment, which element was bombarded with alpha particles to discover the neutron?

20. What conclusion did Rutherford draw from the gold foil experiment?

1. Which experiment led to the discovery of the nucleus?

2. Which element has the stable configuration [Ar] 3d¹⁰ 4s² 4p⁶ 5s²?

3. Which of the following quantum numbers emerge from solving Schrödinger’s equation for the hydrogen atom?

4. The Pfund series of hydrogen corresponds to electron transitions to:

5. According to Planck’s quantum theory, energy is emitted or absorbed in:

6. The quantity in Schrödinger’s equation represents:

7. The first line of the Brackett series corresponds to which transition?

8. Which hydrogen series falls in the infrared region?

9. Which subshell is filled immediately after in the neutral-atom filling order?

10. After is filled, which orbital is filled next in most atoms?

11. According to the rule, which orbital fills before ?

12. Which transition produces the shortest wavelength line in a hydrogen series?

13. The orientation of d-orbitals in space is determined by which quantum number?

14. Which of the following elements has the configuration [He] 2s² 2p²?

15. The number of radial nodes in 5d orbital is:

16. What is the radius of the first Bohr orbit () for hydrogen atom?

17. In classical mechanics, both position and momentum can be measured exactly. Why not in quantum mechanics?

18. Which orbital is oriented along the z-axis with a unique donut-shaped ring?

19. Which principle is closely related to the wave nature of matter proposed by de Broglie?

20. The mathematical expression of the uncertainty principle is:

21. In Rutherford’s gold foil experiment, what was the source of alpha particles?

22. What ultimately fixes the position of a spectral line in either emission or absorption?

23. The Brackett series in hydrogen corresponds to transitions ending at:

24. Which type of spectrum shows bright lines against a dark background?

25. The line spectrum of hydrogen atom provides evidence for:

26. Which of the following d-orbitals has a different shape compared to the others?

27. According to Bohr’s quantization rule, the angular momentum of an electron is:

28. The splitting of spectral lines in a magnetic field is explained by:

29. How many maximum electrons can occupy a single orbital?

30. Which key limitation made the plum pudding model incompatible with atomic emission spectra?

1. If the uncertainty in velocity of an electron is , what is the minimum uncertainty in its position? (Mass of electron )

2. The degeneracy of the energy level with in hydrogen atom is:

3. Which element’s ground-state configuration demonstrates Hund’s rule?

4. The configuration [Ne] 3s² corresponds to:

5. Which element has the configuration [Ar] 4s²?

6. Which orbital has a spherical shape around the nucleus?

7. The number of orbitals in a subshell is given by:

8. How many maximum electrons can occupy a single orbital?

9. In quantum mechanics, an orbital is defined as:

10. Why are half-filled and fully filled subshells more stable?

11. Which particle determines the atomic number of an element?

12. The maximum number of electrons in a p-subshell is:

13. Sodium (Z=11) has which electronic configuration?

14. Which statement distinguishes orbitals from orbits in terms of dimensionality?

15. Which electromagnetic radiation has wavelengths slightly longer than visible red light?

16. The wave–particle duality of electron means:

17. Which subshell is filled immediately after in the neutral-atom filling order?

18. Which of the following is TRUE about spin quantum number?

19. What does the quantum number in Bohr’s model represent?

20. The Balmer- line (H) in the hydrogen spectrum is produced by the transition:

21. The orientation of an orbital in space is determined by:

22. How many p-orbitals exist in each shell where ?

23. Which statement is correct according to Pauli’s principle?

24. Why was the concept of orbit replaced by orbital?

25. In Young’s double-slit experiment, the distance between slits is , wavelength is , and distance to screen is . The fringe width is given by:

26. Which of the following elements has the configuration [He] 2s² 2p²?

27. Which concept is compatible with Heisenberg’s uncertainty principle?

28. Which transition in the hydrogen atom gives the Lyman series?

29. Which of the following statements about d-orbitals is CORRECT?

30. The orientation of an orbital in space is given by:

31. The energy required to remove an electron from level of hydrogen atom is:

32. Which transition in hydrogen corresponds to the Brackett series?

33. What was the major drawback of Dalton’s Atomic Theory?

34. If the wave number of light is , its wavelength is:

35. Which electromagnetic theory of light was given by Maxwell?

36. Which model introduced the concept of atomic orbitals instead of fixed orbits?

37. The maximum number of electrons that can be accommodated in an orbital is:

38. The nucleus of an atom is made up of:

39. Heisenberg’s uncertainty principle is a direct consequence of:

40. The five d-orbitals have orientations described by:

41. Which orbital is non-spherical in shape and has 3 orientations?

42. The frequency of radiation emitted when an electron falls from to is given by:

43. Pauli’s exclusion principle explains which property of matter?

44. If wavelength of radiation is , the photon energy is:

45. Which type of spectrum consists of groups of closely spaced lines, often due to molecules?

46. Which experiment led to the discovery of electrons?

47. Which of the following notations is INCORRECT?

48. Which spectral series of hydrogen lies in the ultraviolet region?

49. Which observation cannot be explained by classical wave theory but is explained by Planck’s quantum theory?

50. The radial probability distribution curve of a 2s orbital shows: