Question: how many nonbonding electron pairs are there in the lewis structure of cn–?
Answer: Let's illustrate these rules by calculating the formal charges on the C and N atoms in the cyanide ion, CN-, which has the Lewis structure: We first count the number of electrons on the C atom. There are 2 from the nonbonding pair of electrons and 3 from the 6 electrons in the triple bond, for a total of 5.