Question

The electronic configuration of an element 'A' is $\left[Ne\right]3s^2$. With which of the following elements it can form an ionic compound of the type $A{X}_2$?

• A. $\left[He\right]2s^{2}2p^2$
• B. $\left[Ne\right]3s^{2}3p^5$
• C. $\left[Ar\right]3d^{10}4s^1$
• D. $\left[Ne\right]3s^{2}3p^4$

Answer 1

Answer: (B)

$\left[Ne\right]3s^{2}3p^5$

The electronic configuration of an element 'A' is $\left[Ne\right]3s^2$.
With $\left[Ne\right]3s^{2}3p^5$ it can form an ionic compound of the type $A{X}_2$.
The element 'A' $\left[Ne\right]3s^2$ can lose 2 electrons to form
$A^{2+}$ ion with electronic configuration $\left[Ne\right]3s^2$.
The element 'X' can gain 1 electron to form $X^{-}$ ion with electronic configuration $\left[Ne\right]3s^{2}3p^5$.