Concerning compounds cyanogen, Hydrogen cyanide and sodium cyanide.

Question

Cyanogen = C2N2 (CN)2

Hydrogen Cyanide = HCN boils at 26C and yeilds an acid solution when added with water.

Sodium Cyanide = empirical formula NaCN is a solid melts at 564C

a) Assuming that the valencies of Hydrogen, Nitrogen and Carbon in these compounds are 1,3 and 4 respectively, draw structual formulae for hydrogen cyanide and cyanogen that are consistent with these valencies

To add further detail, a pair of dots like this, : equals a bond like this -


A pair of dots = a bond like this -. I can't draw triple bonds with the computer. So dots will have to do.
H:C:::N:
:N:::C:C:::N:


In HCN, H has 1 bond, C has 4 and N has 3.
In (CN)2, N has 3 bonds and C has 4.
I hope this helps.