An ion is an atom or group of atoms that has either positive or negative charge.

An ion made of more than 1 atom is called a polyatomic ion.

Ion that easily lose electrons react with atoms that easily gain electrons, they transfer valence electrons to form ionic bonds.

Non-polar bonds are also a type of covalent bond. Unlike polar bonds, non-polar bonds share electrons equally.  

A type of covalent bond between two atoms in which electrons are shared unequally. Because of this, one end of the molecule has a slightly negative charge and the other a slightly positive charge.

A covalent bond is the interatomic linkage that results from the sharing of an electron pair between two atoms.