To determine the names of the polyatomic ions represented by the given chemical formulas, follow these steps:
1. Identify the ion with the formula [tex]\( CN^- \)[/tex]:
- The chemical formula [tex]\( CN^- \)[/tex] is commonly known as cyanide. Cyanide is a polyatomic ion consisting of one carbon (C) atom and one nitrogen (N) atom, with an overall charge of negative one.
2. Identify the ion with the formula [tex]\( HPO_4^{2-} \)[/tex]:
- The chemical formula [tex]\( HPO_4^{2-} \)[/tex] is known as hydrogen phosphate. Hydrogen phosphate is a polyatomic ion that includes one hydrogen (H) atom, one phosphorus (P) atom, and four oxygen (O) atoms, with an overall charge of negative two.
Thus, the polyatomic ion with the formula [tex]\( CN^- \)[/tex] is called cyanide, and the polyatomic ion with the formula [tex]\( HPO_4^{2-} \)[/tex] is called hydrogen phosphate.
