A dot and cross diagram can model the bonding in a simple molecule:
Draw the dot and cross diagram for ammonia, NH3. Nitrogen has five outer electrons because it is in group 5.
Draw the dot and cross diagram for methane, CH4. Carbon has four outer electrons.
Some molecules contain a double bond, which consists of two shared pairs of electrons. For example, oxygen molecules consist of two oxygen atoms joined together. Oxygen atoms can form two covalent bonds, so to link the two oxygen atoms together, a double bond forms.
Nitrogen molecules consist of two nitrogen atoms joined together. Nitrogen atoms can form three covalent bonds, so a triple bond forms between them. The structure of nitrogen is N≡N, showing that it has three shared pairs of electrons.