• Covalent compounds are formed when pairs of electrons are shared between atoms

• Only non-metal elements participate in covalent bonding

• As in ionic bonding, each atom gains a full outer shell of electrons, giving them a noble gas electronic configuration

• When two or more atoms are covalently bonded together, we describe them as ‘molecules’

• Dot-and-cross diagrams can be used to show the electric configurations in simple molecules

• Electrons from one atom are represented by a dot, and the electrons of the other atom are represented by a cross

• The electron shells of each atom in the molecule overlap and the shared electrons are shown in the area of overlap

• The dot-and-cross diagram of the molecule shows clearly which atom each electron originated from

Many simple molecules exist in which two adjacent atoms share one pair of electrons, also known as a single covalent bond (or single bond)