A hydrogen bond is an attractive interaction between a hydrogen atom from one molecule and an electronegative atom (such as oxygen, nitrogen, or fluorine) from another molecule. It is not completed by the transfer of its sole electron to another element. Instead, the hydrogen atom shares its electron with the electronegative atom, creating a partial positive charge on the hydrogen atom and a partial negative charge on the electronegative atom. This electrostatic attraction is what holds the hydrogen bond together.