Question

The electronic configuration of calcium ion $\left(C{a}^{2+}\right)$ is :-

• A. $1s^2,2s^{2}2p^6,3s^{2}3p^6,4s^2$
• B. $1s^2,2s^{2}2p^6,3s^{2}3p^6,4s^0$
• C. $1s^2,2s^{2}2p^6,3s^{2}3p^6,3d^2$
• D. $1s^2,2s^{2}2p^6,3s^{2}3p^6,3d^5$

Answer 1

Answer: (B)

Atomic number of calcium atom is $20$ so it has $20$ electrons
Electronic configuration of calcium atom is- $1s^2,2s^{2}2p^6,3s^{2}3p^6,4s^2$
$Ca$ atom loses two electrons to form $C{a}^{2+}$ ion. These electrons are lost from outermost shell.
The electronic configuration of calcium ion $\left(C{a}^{2+}\right)$ is- $1s^2,2s^{2}2p^6,3s^{2}3p^6,4s^0$