Covalent bonding

• non-metals bond by sharing valence shell electrons to form a covalent bond
• a single covalent bond is an electrostatic attraction between a pair of shared valence electrons and the nuclei of the atoms
• covalent bonds are extremely strong
• bond enthalpy is a measure of bond strength (kJ mol$^{-1}$)
• low melting and boiling points
• good insulators - neutral and no free charge carriers (electrons/ions)
• many are soluble in non-polar solvents
• don't conduct electricity - no delocalised electrons or ions