Because oxygen is more electronegative—electron-greedy—than hydrogen, the Ostart text, O, end text atom hogs electrons and keeps them away from the Hstart text, H, end text atoms. This gives the oxygen end of the water molecule a partial negative charge, while the hydrogen end has a partial positive charge.

The slight positive charges on the hydrogen atoms in a water molecule attract the slight negative charges on the oxygen atoms of other water molecules. This tiny force of attraction is called a hydrogen bond. This bond is very weak.

Since oxygen is more electronegative than hydrogen, the two bonds that are formed will be polar covalent, which means that a partial negative charge will be on the more electronegative atom – oxygen – and two partial positive charges will be on the less electronegative atoms – hydrogen.

The covalent bonds between hydrogen and oxygen atoms in water are polar covalent bonds. The shared electrons spend more time near the oxygen nucleus, giving it a small negative charge, than they spend near the hydrogen nuclei, giving these molecules a small positive charge.

The O2 Lewis structure has a double bond between two oxygen atoms.

The three major types of covalent bonds are single, double, and triple bonds. A carbon atom can form the following bonds: Four single bonds. One double and two single bonds.

four

If we go on to the valence-bond model, in which bonds result from the overlap of atomic orbitals, we see a better explanation: carbon cannot form a quadruple bond because it doesn’t have enough atomic orbitals pointing in the right directions.