Answer:
Neon (Ne)
Step-by-step explanation:
Nitrogen in it's neutral state has valency of 5 and it's electronic configuration is given as;
1s2 2s2 2p3
However in isocyanic acid, it forms a covalent bond with hydrogen and carbon. Due to this bond, it is able to achieve stable octet configuration. The configuration is given as;
1s2 2s2 2p6
This is the same electronic configuration as Neon