# Which atom in the ground state has the same electron configuration as a calcium ion, Ca^(2+) in the ground state?

May 28, 2018

$\text{Argon (Ar)}$

#### Explanation:

Electronic configuration of $\text{_20"Ca}$

${\text{1s"^2\ "2s"^2\ "2p"^6\ "3s"^2\ "3p"^6\ "4s}}^{2}$

Electronic configuration of $\text{_20"Ca"^"2+}$

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

Above electronic configuration is of $\text{_38"Ar}$ at its ground state.