Quantum Numbers and Orbitals: Quiz

Quantum Numbers and Orbitals: Quiz

7 questions

1. Question 1EasyWhich quantum number mainly describes the shape of an orbital?

   AnBlCmₗDmₛ
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   Answer: l

   The angular momentum quantum number l sets the shape: s (l = 0) spherical, p (l = 1) two lobes, d (l = 2) mostly four lobes.

2. Question 2EasyHow many orbitals are in a d subshell?

   A1B3C5D10
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   Answer: 5

   For d, l = 2, so mₗ = −2, −1, 0, +1, +2: five orbitals. 10 is the maximum number of electrons.

3. Question 3EasyWhich subshell does not exist?

   A2sB2dC3pD4f
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   Answer: 2d

   For n = 2, l can only be 0 or 1 (s or p). The first d subshell is 3d.

4. Question 4MediumWhat is the maximum number of electrons in the n = 4 shell?

   A8B16C18D32
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   Answer: 32

   Shell n holds 2n² electrons: 2 × 4² = 32 (4s 2 + 4p 6 + 4d 10 + 4f 14). 16 is the number of orbitals.

5. Question 5MediumWhich set of quantum numbers (n, l, mₗ, mₛ) is allowed?

   A(3, 1, −2, +½)B(3, 3, 0, −½)C(3, 2, −1, +½)D(0, 0, 0, +½)
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   Answer: (3, 2, −1, +½)

   For n = 3, l can be 2, and mₗ = −1 lies between −2 and +2. (3, 1, −2) has |mₗ| > l; (3, 3) has l = n; n cannot be 0.

6. Question 6MediumWhich subshell has n = 4 and l = 1?

   A4sB4pC4dD1p
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   Answer: 4p

   l = 1 is a p subshell, and n = 4 is the shell: 4p, with 3 orbitals and up to 6 electrons.

7. Question 7HardHow many radial nodes does a 4s orbital have?

   A0B1C3D4
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   Answer: 3

   Radial nodes = n − l − 1 = 4 − 0 − 1 = 3. An s orbital has no angular nodes (l = 0), so all n − 1 = 3 nodes are radial.