Textbook Question
The Ti2 + ion is isoelectronic with the Ca atom. (b) Calculate the number of unpaired electrons for Ca and for Ti2+.
10. Periodic Properties of the Elements
The Electron Configuration: Ions
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What is the full electron configuration of the selenide ion?
A
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p4
B
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6
C
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p4 5s2
D
1s2 2s2 2p6 3s2 3p6 4s2 3d8 4p4 5s2 5p2
Verified step by step guidance1
Identify the neutral atom: Selenium (Se) is the neutral atom for the selenide ion. Its atomic number is 34, which means it has 34 electrons in its neutral state.
Write the electron configuration for the neutral selenium atom: The electron configuration for selenium is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p4.
Determine the charge of the selenide ion: The selenide ion (Se2-) has gained 2 additional electrons compared to the neutral selenium atom.
Add the extra electrons to the electron configuration: Since the selenide ion has 2 extra electrons, add these to the next available subshell, which is the 4p subshell. This changes the 4p4 to 4p6.
Write the full electron configuration for the selenide ion: The electron configuration for the selenide ion is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6.
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