What are the differences between ionic polar covalent nonpolar covalent and hydrogen bonds?

Ionic bonds involve the transfer of electrons between atoms with very different electronegativities, resulting in the formation of cations and anions that are attracted to each other. Polar covalent bonds occur when electrons are shared unevenly between atoms with different electronegativities, creating a partial negative and partial positive charge. Nonpolar covalent bonds involve equal sharing of electrons between atoms with similar electronegativities. Hydrogen bonds are weak interactions between a hydrogen atom covalently bonded to an electronegative atom (such as oxygen or nitrogen) and another electronegative atom.