The electronic configuration of Ca is

Options

A. `[Kr]4s^(2)`
B. `[Ar]4s^(2)`
C. `[Ne]4s^(2)`
D. `[He]4s^(2)`

Answer

B

Explanation

Atomic number of Ca is 20. thus, its electronic configuraiton is
`1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2)` or `[Ar]4s^(2)`
The atoms of al alkaline earth metals have two s electrons in their outtermost shell `(ns^(2))`. As these elements have similar valency shell electronic configuration, they show regular gradation in their physical properties and exhibit similar chemical properties.