The methyl ion (CH₃^–) consists of a carbon (C) atom that is bonded to three hydrogen (H) atoms. Its molecular structure is shown below.

Let us calculate the formal charges on C and H and then determine the formal charge of CH₃^–.

Carbon

V = 4, N = 2, B = 6

Therefore,

q_f = 4 – 2 – 6/2 = -1

Theformal charge on C in CH₃^– is -1.

All Three Hydrogen Atoms

V = 1, N = 0, B = 2

Therefore,

q_f = 1 – 0 – 2/2 = 0

The net formal charge is: -1 + 3 x 0 = -1

The formal charge of CH₃^–is zero.