Question

How many electrons does nitrogen (N) need to gain to have a stable outer electron shell

Answer 1

It need "3 electrons" to have a stable electronic configuration. 

'cause it has 5 electrons in it's outer shell & every atom needs 8 electrons. So, it requires 3 more!

Hope this helps!

Answer 2

Answer: 3 more electrons

Explanation: Generally elements with inert gas configuration are more stable. It is also called as Octet rule.

It tells that, elements which have electrons equal to atomic number of inert gases (2,8,10,18,36 etc) in their valency shell are exceptionally stable.

Here in our case, nitrogen has atomic number-7, 1s2 2s2 2p3

Here N has 5 electrons in valency shell , hence it needs 3 more electrons to get octet configuration.

So answer is 3 Electrons