Lewis structure for hydrogen cyanide is H:C:::N:
Hydrogen has valence one (I), it means it has one single bond and elctron configuration like closest noble gas helium.
Carbon has valence four (IV), it has four bonds (one with hydrogen and three with nitrogen) and full octet.
Nitron has valence three (III), it has full octet and electron configuration like noble gas neon (Ne).
Hydrogen cyanide has linear shape (the bond angles of 180 degrees).
