# How many electrons will a calcium atom (Ca) lose in order to get a noble gas configuration?

Oct 5, 2014

Calcium atoms will lose two electrons in order to achieve the noble gas configuration of argon. A neutral calcium atom has 20 electrons, while a calcium atom that has lost two electrons will have 18 electrons, and a neutral argon atom also has 18 electrons.

A neutral calcium atom, $\text{_20"Ca}$, has 20 electrons with an

electron configuration of ${\text{1s"^2"2s"^2"2p"^6"3s"^2"3p"^6"4s}}^{2}$.

An calcium cation, ${\text{_20"Ca}}^{2 +}$, has 18 electrons with an electron

configuration of ${\text{1s"^2"2s"^2"2p"^6"3s"^2"3p}}^{6}$.

A neutral argon atom, $\text{_18"Ar}$, has 18 electrons with an electron

configuration of ${\text{1s"^2"2s"^2"2p"^6"3s"^2"3p}}^{6}$, the same as a ${\text{Ca}}^{2 +}$ cation.