Explain ion in chemistry

i need help with ion i know what they do, but are they only between a metal and nonmetal or a positive and negative charge atom?

2. are polar covalent only between non mental bonds?

An ion is not between anything. It is just one atom. It has either lost some electrons or gained some electrons. But if you mean ionIC BOND (which is what I think you mean) then it is between a metal and nonmetal-most of the time- but you dont need to know exceptions for chem(if its just honors)

Polar covalent means that the bond is between two nonmetals. The polar part means that these two nonmetals share the electrons UNequally- this means that one of nonmetals pulls the electron in more than the other nonmetal. In contrast, NONpolar covalent is sharing of electrons by two nonmetals equally.

Hope that makes sense :)