Covalent bonding

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• A covalent bond is formed between non metal atoms, which combine together by sharing electrons. Covalent compounds have no free electrons and no ions so they don't conduct electricity.
• Non metals combine together by sharing electrons. The shared pair of electrons holds the two atoms together. It's called a covalent bond. The group of atoms bonded together in this way is called a molecule.
• Dot and cross models show how a pair of electrons forms a covalent bond. Notice that in the diagrams in the table below only the electrons in the outer shell of each atom are shown.
• All the Group 1 elements: Li, Na, K, Rb, Cs and Fr, have one electron in the outer shell.
• The Group 7 elements: F, Cl, Br, I and As have seven electrons in the outer shell.
• Group 0 elements: He, Ne, Ar, Kr, Xe and Rn have full outer shells. (Group 0 is sometimes called Group 8.)

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