Question

How do you draw the Lewis Structure for `HNO_3`?

Answer 1

`O=N^(+)(-O^-)(O-H)`

Explanation:

There are `5+3xx6+1=18" electrons"` to distribute over 4 centres. There are 2 formal charges in the Lewis structure, i.e. on one of the oxygens and on the quaternized nitrogen.

The left most oxygen is neutral (with 2 lone pairs, and with the double bond it has the 6 valence electrons required for neutrality). The nitrogen has a share of 4 electrons, and thus is formally positive (i.e. with 2 inner core electrons, there are 6 electrons only to balance the +7 nuclear charges. To balance this positive charge, the next oxygen has 7 valence electrons (9 in total), and thus a formal negative charge. The hydroxyl group is formally neutral.