I have to draw Lewis structures for hydrogen cyanide and cyanogen with nitrogen valency of three. Would I still need 2 dots after the N in hydrogen cyanide or would this represent nitrogen with a valency of 5?

Question

I have to draw Lewis structures for hydrogen cyanide and cyanogen with nitrogen valency of three. Would I still need 2 dots after the N in hydrogen cyanide or would this represent nitrogen with a valency of 5?

Yes. THose two "dots" are unshared electrons.

Thanks. When writing the structural formula for HCN I have done as follows H-C=N with triple lines not double between C and N. Is that correct for a structural formula with nitrogen valency of three?

yes.

Answer 1

Yes, you are correct. The structural formula for hydrogen cyanide (HCN) with nitrogen having a valency of three should be written as H-C≡N, where the triple line represents a triple bond between the carbon (C) and nitrogen (N) atoms. This indicates that there are three shared electron pairs between C and N, and the nitrogen atom fulfills its valency of three.