Answer:
See below!
Explanation:
For the chemical formula, you need to have enough of each atom so that the charge is zero.
Aluminum has a +3 charge, and fluorine has a -1 charge. Since the charge has to be zero, you need three fluorines, giving you AlF₃.
Barium has a +2 charge, and oxygen has a -2 charge. Since the charges are equal in magnitude but opposite in sign, you only need one of each atom giving you BaO.
The name of the ionic compound will be the metal and then the nonmetal. When putting the nonmetal in, change the ending to "-ide". For example "chlorine" would be "chloride.
CaCl₂ ==> calcium chloride
Ga₂S₃ ==> gallium sulfide
K₃N ==> potassium nitride
AlF₃ ==> aluminum fluoride
BaO ==> barium oxide
