We’re being asked to assign the charges to each atom in each compound given.
We’re going to use + and – for ionic compounds and δ+ and δ- for covalent bonds where electrons are not equally shared.
Let’s first define an ionic and molecular bond:
• involves the transferring of an electron from one element to another element
• positively charged ion + negatively charged ion
▪ metal → usually is the positively charged ion (+)
▪ nonmetal → usually is the negatively charged ion (-)
▪ metal(or polyatomic ion) + nonmetal (or polyatomic ion)
Covalent (or Molecular) Bond
• involves the sharing of electron(s) between elements
▪ nonmetal + nonmetal