Question

why negative sign is after valency ( like for nitrite, it's NO^2- and not NO^-2) ?

Answer 1

Answer:

The oxygen atom bonded by a single bond has only one electron involved in bonding, and so contains one unpaired electron. Hence, in order to complete its octet it acquires one additional electron. As a result of this, the nitrite ion has an overall charge of -1.

Explanation:

i hope you understood