TRB PG Assistant - Atomic structure, term symbols, coupling schemes and spectra of many‑electron systems One Line Questions & Answers

1. The azimuthal quantum number (l) for a p orbital is: — 1

2. What is the value of L for a D term? — 2

3. What is the value of L for a P term? — 1

4. What is the value of L for an S term? — 0

5. The spin quantum number (ms) can have which values for an electron? — +1/2, -1/2

6. If L=1 and S=1, what are the possible J values? — 0, 1, 2

7. For a system with total spin quantum number S=1/2, the multiplicity (2S+1) is: — 2

8. For a system with total spin quantum number S=1, the multiplicity (2S+1) is: — 3

9. What is the term symbol for the ground state of a Carbon atom (atomic number 6)? — ³P

10. What is the ground state term symbol for a p² electron configuration? — ³P

11. What is the ground state term symbol for a d² electron configuration? — ³F

12. What is the term symbol for the ground state of a Boron atom (atomic number 5)? — ¹S

13. What is the ground state electron configuration of Helium (He)? — 1s²

14. In the term symbol 2S+1L_J, the number of possible values for J is (2S+1) if L >= S, and (2L+1) if S >= L. For a ³D term (S=1, L=2), what are the possible J values? — 0, 1, 2

15. If L=2 and S=1/2, what are the possible J values? — 3/2, 5/2

16. Which of the following terms is NOT possible for a d¹ electron configuration? — ³D

17. What is the term symbol for a p¹ electron configuration? — ²P

18. In the context of atomic spectra, what does the term 'multiplet' refer to? — A group of closely spaced spectral lines arising from a single term that is split into several levels due to spin-orbit coupling.

19. Spin-orbit coupling is more significant for atoms with: — Higher atomic numbers

20. In LS-coupling, the total orbital angular momentum (L) and total spin angular momentum (S) are coupled to form: — The total electronic angular momentum (J)

21. Which type of spectroscopy is used to study electronic transitions in atoms and molecules? — Ultraviolet-Visible (UV-Vis) spectroscopy

22. What does the J-value (total angular momentum quantum number) represent in the context of atomic spectra? — It represents the vector sum of total orbital and total spin angular momenta.

23. The spectral lines observed in the emission spectrum of hydrogen are due to transitions between different energy levels. These transitions are governed by: — Selection rules

24. Which coupling scheme is typically dominant for lighter atoms? — LS-coupling (Russell-Saunders coupling)

25. For a given term symbol, the number of possible J values depends on the relationship between L and S. If L > S, the possible J values range from: — L+S down to |L-S|

26. Which coupling scheme becomes more important as the atomic number increases due to the increasing strength of spin-orbit coupling? — jj-coupling

27. Which coupling scheme is typically dominant for heavier atoms? — jj-coupling

28. Spectroscopy is the study of the interaction between: — Matter and electromagnetic radiation

29. What is the fundamental principle behind the formation of Hund's rules? — Minimization of electrostatic repulsion between electrons and maximization of spin multiplicity.

30. According to the Pauli Exclusion Principle, no two electrons in an atom can have the same set of which quantum numbers? — n, l, ml, ms

31. Which quantum number describes the shape of an atomic orbital? — Azimuthal or angular momentum quantum number (l)

32. The fine structure of atomic spectra is primarily due to: — Relativistic effects and spin-orbit coupling

33. In the context of atomic structure, what does 'term symbol' represent? — The total electronic state of an atom or molecule

34. What does the magnetic quantum number (ml) specify for an electron in an atom? — The orientation of the orbital in space

35. Hund's Rule of Maximum Multiplicity states that for a given electron configuration, the term with the highest multiplicity is: — The lowest in energy

36. Atomic spectra provide information about: — The electronic energy levels of an atom

37. The multiplicity of a term symbol (2S+1) indicates: — The number of possible orientations of the spin angular momentum

38. Hund's Rule of Maximum Multiplicity is a consequence of: — Electrostatic repulsion between electrons

39. The spectral lines from many-electron systems are often more complex than those from one-electron systems due to: — The presence of multiple electrons, leading to various possible electronic states and interactions.

40. Which of the following is a consequence of the electrostatic interaction between electrons in a many-electron atom? — The splitting of terms into different energy levels.

41. A term symbol is typically represented as 2S+1L_J. What does the 'S' in 2S+1 represent? — The total spin angular momentum quantum number

42. In a term symbol 2S+1L_J, what does the 'L' represent? — The total orbital angular momentum quantum number

43. In a term symbol 2S+1L_J, what does the 'J' represent? — The total angular momentum quantum number

44. In jj-coupling, the individual electron orbital angular momentum (l_i) and spin angular momentum (s_i) are first coupled to form j_i, and then these are coupled to form: — Total electronic angular momentum (J)

45. The splitting of spectral lines in a magnetic field is known as: — Zeeman effect

46. The splitting of spectral lines in an electric field is known as: — Stark effect

47. Which phenomenon involves the splitting of spectral lines due to the interaction of electron spins with orbital angular momentum? — Spin-orbit coupling

48. The energy difference between two electronic states in an atom is related to the frequency (ν) of the absorbed or emitted photon by the equation: — ΔE = hν

49. Another common selection rule for electric dipole transitions in atomic spectra is ΔJ = 0, ±1 (excluding J=0→J=0). What is the rule for Δl (change in orbital angular momentum quantum number of a single electron)? — Δl = ±1

50. The selection rules for electronic transitions in atomic spectra dictate which transitions are allowed. For electric dipole transitions, a common rule is ΔL = 0, ±1 (excluding 0→0). What is the rule for ΔS? — ΔS = 0

Atomic structure, term symbols, coupling schemes and spectra of many‑electron systems - One Line Questions