What is the charge on the sulfate ion?

The sulfate ion has a charge of 2-. This can be understood by examining the composition of the sulfate ion, which is chemically represented as SO₄²⁻.

The sulfate ion consists of one sulfur atom covalently bonded to four oxygen atoms. In this configuration, sulfur typically exhibits a +6 oxidation state, while each oxygen generally has a -2 oxidation state. The overall charge of the sulfate ion results from the sum of the oxidation states of the atoms within the ion.

Calculating the charge:

• The contribution from sulfur is +6.
• The contribution from the four oxygen atoms is 4 × (-2) = -8.
• When combined, the total charge is +6 - 8 = -2.

Therefore, the sulfate ion has a net charge of 2-. This distinguishes it from other ions with different total charges or those that are neutral, explaining why this choice is the correct one among the options given.