Summary:
- A polyatomic ion is a group of atoms that are covalently bonded together and which carry an overall electrical charge.
- The charge of the ion is reflected in the number of total valence electrons in the structure.
- The Lewis structure for the sulfate ion consists of a central sulfur atom with four single bonds to oxygen atoms.
- This yields the expected total of 32 electrons.
- Since the sulfur atom started with six valence electron, two of the S-O bonds are coordinate covalent.
- The less electronegative sulfur atom is the central atom in the Structure.