Question

What is the electron configuration of Ca+2?

Answer 1

The electron configuration of a `"Ca"^(2+)"` ion is `"1s"^2"2s"^2"2p"^6"3s"^2"3p"^6"`.

Explanation:

The atomic number of calcium is 20. This means that in a neutral calcium atom, there are 20 protons in its nucleus. A neutral calcium atom also has 20 electrons. The electron configuration of a neutral calcium atom is `"1s"^2"2s"^2"2p"^6"3s"^2"3p"^6"4s"^2"`.

A calcium `2+` ion has lost its two valence electrons, and now has `18` electrons. The electron configuration of a `"Ca"^(2+)"` ion is `"1s"^2"2s"^2"2p"^6"3s"^2"3p"^6"`, which is isoelectronic with the noble gas argon.