# Question #15936

Dec 14, 2017

$X {Y}_{2}$

#### Explanation:

e.g. $M g C {l}_{2}$, $B a B {r}_{2}$

Atom X requires two electrons to fill its valence shell
Atom Y requires one electron to fill its valence shell

Therefore, atom X forms two bonds with two Y atoms.

See an example below, with the dot and cross diagram to show the ionic bonding: