Complete the paragraph below, which describes ionic compounds:
Ionic substances are made of both cations and anions. Cations have a ..... charge, whereas anions have a ..... charge. Cations are formed when metal atoms ..... one or more electrons. Anions are formed when non-metals ..... one or more electrons. As oppositely charged ions are attracted to each other, ionic compounds are normally formed between metallic elements and ..... elements, although there are exceptions.