Question

part 3 (1 point)
which of the following statements is true about the two lewis structures?
choose one:
hcn has more formal charges than hnc.
hcn has fewer formal charges than hnc.
both hcn and hnc have +1 and -1 formal charges, but in hcn the negative formal charge is on the more electronegative atom.
both hcn and hnc have +1 and -1 formal charges, but in hcn the negative formal charge is on the less electronegative atom.

Explanation:

When drawing Lewis - structures of HCN and HNC, both have a total of 10 valence electrons. In HCN, the structure is H - C≡N, and in HNC, it is H - N≡C. The formal charge formula is $FC = V - \frac{1}{2}B - L$, where $V$ is the number of valence electrons of the free atom, $B$ is the number of bonding electrons, and $L$ is the number of non - bonding electrons. Both HCN and HNC have formal charges of + 1 and - 1. Nitrogen is more electronegative than carbon. In HCN, the negative formal charge is on the nitrogen (more electronegative) atom.

Answer:

Both HCN and HNC have +1 and -1 formal charges, but in HCN the negative formal charge is on the more electronegative atom.