# Why is Ca(NO_3)_2 a ionic bond? I thought all of them are nonmetals so it should be a covalent bond?

Nov 14, 2017

The nitrate ion, $N {O}_{3}^{-}$ is a discrete species.....

And calcium is a METAL......

#### Explanation:

You look at the Lewis formulation of nitrate, THREE of the four atoms bear formal charges....

$O = \stackrel{+}{N} {\left(- {O}^{-}\right)}_{2} \equiv N {O}_{3}^{-}$

We say that the nitrogen is quaternized and has donated its lone pair to an oxygen atom.....the charge is balanced by the tow oxygen atoms that bear a formal negative charge....

Calcium is in Group 2 of the Periodic Table, so it typically forms $C {a}^{2 +}$ upon oxidation.....

$C a \left(s\right) + \Delta \rightarrow C {a}^{2 +} + 2 {e}^{-}$

The salt balances charge....and so $C {a}^{2 +} + 2 \times N {O}_{3}^{-}$ gives...

$C a {\left(N {O}_{3}\right)}_{2}$...........as the salt of a metal and an acid.