3 d. Hg⁺² and S<sup>-2

Need to make the compound neutral by balancing positive and negative ions:
Need one mercury and one sulfur

HgS</sup>

two non metals? no
metal/nonmetal? yes
metal with more than one charge?yes

Hg has a charge of +2 and compound is binary so -ide on end of nonmetal

mercury (II) sulfide