Answer:
Negative; positive
Step-by-step explanation:
Whenever we have an ionic substance, by convention, we firstly write a symbol of a metal we have. Metals tend to lose their electrons to make ionic compounds and become positively charged species, also known as cations.
Similarly, the metal cation in an ionic substance is followed by a nonmetal. Nonmetal atoms tend to gain the electrons lost by the metals in order to become negatively charged species, also known as anions.
That said, at the front of the compound we have a cation with the positive charge and at the back of the compound we have an anion with the negative charge.