Question

$Ca^{2 +}$is isoelectronic with.

• A. Na
• B. $Mg^{2 +}$
• C. $Ba^{2 +}$
• D. Ar

Answer 1

Answer: (D)

Ar

Answer 2

: Atomic no. of Ca = 20

$Ca^{2 +} = 1s^{2}2s^{2}2p^{6}2s^{2}3p^{6}$

$Ar = 1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}$