Distinguish between ionic bonds, covalent bonds and hydrogen bonds

To put it simply, ionic bonds form when one atom transfers an electron to another atom. The atom that gains an electron becomes a negative ion while the atom that loses an electron becomes a positive ion. Covalent bonds form when two atoms share electrons. A hydrogen bond is when you have a negatively charged O, N, or F atom in one molecule, a positively charged H atom latched on to an O, N or F atom in another molecule. An example of a hydrogen bond is water.