Using Lewis structures and formal charge, which of the following ions is most stable? OCN⁻ ONC⁻ NOC⁻
A) OCN⁻
B) ONC⁻
C) NOC⁻
D) None of these ions is stable according to Lewis theory.

Question

Quizplus · Accepted Answer

To determine stability using Lewis structures and formal charge, we want the formal charges to be as close to 0 as possible. 
For the OCN⁻ ion, oxygen has 6 valence electrons, each nitrogen and carbon have 4, and the negative charge provides an additional electron. This gives a total of 18 valence electrons. 
The Lewis structure for OCN⁻ shows that each atom has a full octet, and the formal charges are 0 for each atom. 
For ONC⁻, the Lewis structure is identical to that of OCN⁻ but with a different atom in the middle. This also results in a full octet for each atom and formal charges of 0. 
NOC⁻, on the other hand, has a different Lewis structure in which nitrogen has only 6 valence electrons instead of 8. This results in a formal charge of +1 for nitrogen and -1 for oxygen and carbon. NOC⁻ is therefore less stable than OCN⁻ and ONC⁻.

Using Lewis Structures and Formal Charge, Which of the Following