Bonding

• Ionic bonding - When a metal and a non-metal react, the metal atom loses electrons and the non-metal gains them.
• Losing electrons - positive ion. Gaining electrons - negative ion.
• Ionic bonding is the transfer of electrons.
• An ionic compound is a giant structure of ions with a regular, repeating arrangement called an ionic lattice.
• Ionic compounds have high melting and boiling points due to the large amounts of energy needed to break the strong bonds.
• Ionic compounds conduct electricity when melted or in solution, but are insulators when solid.
• Polymers are very large molecules with atoms joined by strong covalent bonds, forming chains of variable lengths.
• Polymers melt at high temperatures. They are solids at room temperature. This is because their intermolecular forces are strong and therefore hard to break.
• When non-metal atoms bond together, they share pairs of electrons to form covalent bonds.
• Covalent bonds are very strong because the positively charged nuclei of the bonded atoms are attracted to the shared pair of electrons by electrostatic forces.
• Covalent bonding - Atoms only share electrons in their outer shell.
• Each single covalent bond provides one extra electron for each atom.
• Covalent bonding occurs in compounds of non-metals and non-metal elements.
• Metallic bonding involves delocalised electrons.
• Metallic bonding - Outer shell electrons in metal atoms are delocalized and strongly attracted to the positive metal ions.
• Forces of attraction hold the atoms together in a regular structure and are known as metallic bonding.
• Substances held together by metallic bonds include metallic elements and alloys.
• The delocalised electrons in metallic bonds produce all the properties of metals.
• Metals exhibit giant atomic structures held together by strong metallic bonding, resulting in high melting and boiling points.