Multiple Choice
The electron configuration of Fe^{2+} is [Ar] 3d^6. Which of the following is true about Fe^{2+}?
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10. Periodic Properties of the Elements
The Electron Configuration: Ions
Multiple Choice
Which of the following is the correct ground-state electron configuration for the Cd^{2+} ion?
A
[Kr] 4d^{10}
B
[Kr] 4d^{8} 5s^{2}
C
[Kr] 4d^{10} 5s^{2}
D
[Xe] 4f^{14} 5d^{10}
Verified step by step guidance1
Identify the atomic number of cadmium (Cd), which is 48, meaning a neutral Cd atom has 48 electrons.
Write the ground-state electron configuration for neutral Cd. Recall that Cd is in period 5 and group 12, so its configuration ends with 5s and 4d orbitals filled.
Determine the electron configuration for the Cd^{2+} ion by removing 2 electrons from the neutral atom. Remember that electrons are removed first from the outermost shell (highest principal quantum number n).
Remove the 2 electrons from the 5s orbital (since 5s has higher energy than 4d in transition metals when ionizing), resulting in a configuration with a filled 4d subshell and no electrons in 5s.
Express the final electron configuration for Cd^{2+} using the noble gas shorthand notation, which should be [Kr] 4d^{10}.
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