Questions on Hund's Rule and Orbital Filling Diagrams
20 Multiple-Choice Questions — Hund's Rule and Orbital Filling Diagrams
1. What does Hund’s Rule state about electrons in degenerate orbitals?
A) They pair up immediately
B) They fill empty orbitals singly before pairing
C) They occupy the lowest energy orbital first
D) They must have opposite spins
E) They fill orbitals randomly
2. In the p subshell with three degenerate orbitals, how do electrons fill according to Hund’s Rule?
A) All electrons pair in the first orbital before moving to the next
B) One electron occupies each orbital singly before any pairing occurs
C) Electrons skip the p subshell and fill d subshell first
D) Two electrons occupy the same orbital with opposite spins immediately
E) Electrons randomly distribute across orbitals
3. How is the electron spin arranged when electrons singly occupy orbitals in the same subshell as per Hund’s Rule?
A) All spins are opposite
B) Spins alternate randomly
C) All electrons have parallel (same) spins
D) Spins cancel out
E) Spin does not matter in Hund’s Rule
4. What is the main reason behind Hund’s Rule?
A) To minimize electron-electron repulsion
B) To maximize atomic mass
C) To obey the Pauli Exclusion Principle
D) To fill orbitals as quickly as possible
E) To maximize energy
5. Which of the following diagrams correctly represents the orbital filling for the 2p subshell with four electrons?
A) ↑↓ ↑ ↑
B) ↑ ↑ ↑ ↑
C) ↑↓ ↑↓ ↑
D) ↑ ↑ ↑ ↓
E) ↑↓ ↓↓ ↑
6. According to Hund’s Rule, how many unpaired electrons are in the nitrogen atom (1s² 2s² 2p³)?
A) 0
B) 1
C) 2
D) 3
E) 4
7. How does Hund’s Rule affect the total spin of electrons in partially filled orbitals?
A) It minimizes total spin
B) It maximizes total spin
C) It has no effect on spin
D) It forces spins to be zero
E) It randomizes spin
8. In an orbital filling diagram, what symbol typically represents an electron with spin-up?
A) ↑
B) ↓
C) ↔
D) →
E) ←
9. Which principle must also be satisfied alongside Hund’s Rule in orbital filling?
A) Heisenberg Uncertainty Principle
B) Aufbau Principle
C) Boyle’s Law
D) Charles’s Law
E) Law of Conservation of Mass
10. In the orbital filling diagram for oxygen’s 2p electrons (2p⁴), how many orbitals contain paired electrons?
A) 0
B) 1
C) 2
D) 3
E) 4
11. What is the maximum number of electrons that can occupy a single orbital according to Hund’s Rule?
A) 1
B) 2
C) 3
D) 4
E) 5
12. Which of the following is not true about Hund’s Rule?
A) Electrons occupy empty orbitals singly before pairing
B) Electrons in singly occupied orbitals have parallel spins
C) Electron pairing is delayed to minimize repulsion
D) Electrons in paired orbitals have opposite spins
E) Electrons in degenerate orbitals fill randomly
13. How many electrons are unpaired in the 3d⁵ configuration (e.g., Mn)?
A) 0
B) 1
C) 3
D) 5
E) 10
14. What does an orbital filling diagram primarily represent?
A) The number of protons in an atom
B) The arrangement of electrons in atomic orbitals
C) The shape of molecules
D) The mass number of an isotope
E) The rate of chemical reactions
15. Which of the following electron configurations violates Hund’s Rule?
A) 1s² 2s² 2p² with electrons in different 2p orbitals having parallel spins
B) 1s² 2s² 2p³ with one electron in each 2p orbital
C) 1s² 2s² 2p⁴ with two electrons paired in the same 2p orbital while one orbital is empty
D) 1s² 2s² 2p⁶ full p orbitals
E) 1s² 2s² 2p¹ with a single electron in a p orbital
16. Hund’s Rule helps to explain the:
A) Color of transition metals
B) Magnetic properties of atoms
C) Mass of isotopes
D) Shape of ionic crystals
E) Rate of diffusion
17. What is the electron configuration of carbon (atomic number 6) using orbital filling diagrams and Hund’s Rule?
A) 1s² 2s² 2p¹ 2p¹
B) 1s² 2s² 2p² (with electrons paired in one 2p orbital)
C) 1s² 2s² 2p¹ 2p¹ (electrons in separate 2p orbitals with parallel spins)
D) 1s² 2s² 2p³
E) 1s² 2s¹ 2p³
18. How many orbitals are fully filled in the 3p⁶ subshell?
A) 1
B) 2
C) 3
D) 4
E) 6
19. The term “degenerate orbitals” means:
A) Orbitals with the same energy
B) Orbitals with different energies
C) Orbitals with paired electrons
D) Orbitals with opposite spins
E) Orbitals in different shells
20. When drawing orbital filling diagrams, which of these is correct?
A) Fill orbitals with two electrons before moving to the next orbital
B) Fill orbitals singly first with parallel spins, then pair electrons
C) Always fill the highest energy orbitals first
D) Place electrons in any order as long as the number is correct
E) Electrons in the same orbital have the same spin
Answers with Explanations
1. B — Electrons fill degenerate orbitals singly before pairing.
2. B — One electron in each of the three p orbitals before pairing.
3. C — Spins are parallel (same direction) when singly occupying orbitals.
4. A — Minimizes electron-electron repulsion for stability.
5. A — Correct filling: two paired electrons in first p orbital, and one electron singly in next.
6. D — Nitrogen has 3 unpaired electrons in the 2p orbitals.
7. B — Hund’s Rule maximizes total spin by filling orbitals singly with parallel spins.
8. A — Up arrow (↑) typically represents spin-up electron.
9. B — Aufbau Principle complements Hund’s Rule in electron filling order.
10. B — Oxygen has 1 paired orbital (with 2 electrons) and 2 singly occupied orbitals in 2p.
11. B — Maximum 2 electrons per orbital with opposite spins.
12. E — Electrons do not fill degenerate orbitals randomly; they follow Hund’s Rule.
13. D — 3d⁵ has 5 unpaired electrons, each occupying separate orbitals singly.
14. B — It represents how electrons occupy atomic orbitals.
15. C — This configuration violates Hund’s Rule by pairing electrons before filling all orbitals singly.
16. B — Hund’s Rule explains magnetic behavior due to unpaired electrons.
17. C — Carbon fills 2p orbitals singly with parallel spins (2p¹ 2p¹).
18. C — 3p subshell has 3 orbitals, fully filled means all 3 orbitals with paired electrons.
19. A — Degenerate orbitals have the same energy level.
20. B — Fill orbitals singly with parallel spins before pairing electrons.
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