Give the formal change on the sulfur atom in a Lewis structure for the sulfate ion in which every atom satisfies the octet rule.
6 v.e - 4 v.e. = formal charge of +2?
right
To determine the formal charge on an atom in a Lewis structure, you need to follow these steps:
1. Count the number of valence electrons in the neutral atom. For sulfur (S), it is in Group 6A, so it has 6 valence electrons (v.e).
2. Assign one valence electron to every bond the atom forms with another element. In the case of the sulfate ion (SO₄²⁻), each oxygen (O) atom will form a double bond with the sulfur (S) atom, resulting in a total of 4 bonds. Therefore, the sulfur atom has used up 8 valence electrons (4 × 2 e⁻ = 8 e⁻) in the bonds.
3. Distribute the remaining valence electrons around the atom to fill the octet rule. Since sulfur started with 6 valence electrons and has used 8 in bonding, it has 6 - 8 = -2 valence electrons.
4. Calculate the formal charge by subtracting the assigned electrons from the original valence electrons. In this case, the formal charge on sulfur is 6 - 8 = -2.
So, the formal charge on the sulfur atom in the sulfate ion is -2, not +2 as you mentioned.