Multiple Choice
How many subshells are present in the n = 4 shell?
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10. Periodic Properties of the Elements
The Electron Configuration: Quantum Numbers
Multiple Choice
Give the set of four quantum numbers that represent the indicated electron in each of the following elements.
Cl– (18th electron)
A
n = 3; l = 0; ml = +1; ms = -1/2
B
n = 3; l = 0; ml = -1; ms = -1/2
C
n = 3; l = 2; ml = +1; ms = -1/2
D
n = 3; l = 1; ml = +1; ms = +1/2
E
n = 3; l = 1; ml = +1; ms = -1/2
Verified step by step guidance1
Identify the electron configuration of Cl⁻. Chlorine (Cl) has an atomic number of 17, so it has 17 electrons. As Cl⁻, it gains an extra electron, making it 18 electrons in total.
Write the electron configuration for Cl⁻: 1s² 2s² 2p⁶ 3s² 3p⁶. The 18th electron is in the 3p orbital.
Determine the principal quantum number (n). For the 3p orbital, n = 3.
Determine the azimuthal quantum number (l). For a p orbital, l = 1.
Determine the magnetic quantum number (mₗ) and the spin quantum number (mₛ). The 3p orbital can have mₗ values of -1, 0, +1. The electron is the last one added, so it will have mₗ = +1 and mₛ = -1/2, as it pairs with an existing electron in the orbital.
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