Which of the following compounds contains a sulfur atom and has a 2- charge?

The compound that contains a sulfur atom and carries a 2- charge is sulfur trioxide, represented as SO3(2-). This ion, known as sulfite, features one sulfur atom bonded to three oxygen atoms. The overall 2- charge comes from the presence of oxygen atoms, which are typically more electronegative and can contribute to the negative charge in the structure.

While other compounds listed also contain sulfur, they either have a different charge or structure. For instance, sulfur tetraoxide (SO4(2-)) is similarly a sulfur-containing species but has a distinct 2- charge associated with the overall structure, while thiosulfate (S2O3(2-)) contains two sulfur atoms, not just one. Additionally, hydrogen sulfate (HSO4(-)) includes sulfur but has a -1 charge rather than -2. Thus, the identification of sulfite as SO3(2-) is accurate due to its specific composition and charge.