8) Metallic Bonding:

Metallic Bonding Involves Delocalised Electrons

1. Metals consist of a giant structure where the electrons in the outer shell of the metal atoms are delocalised (free to move around).

2. There are strong electrostatic forces of attraction between the positive metal ions and the delocalised electrons, holding the atoms together in a regular structure.

3. These forces of attraction are called metallic bonding, which is very strong.

Properties of Metals

1. Metallic elements and alloys are held together by metallic bonding.

2. The delocalised electrons in metallic bonds are responsible for the typical properties of metals.

Most Metals Are Solid at Room Temperature

1. The strong electrostatic forces between metal atoms and the delocalised electrons require a lot of energy to break.

2. This results in high melting and boiling points, meaning most metals are solid at room temperature.

Metals Are Good Conductors of Electricity and Heat

1. Delocalised electrons can carry both electric charge and thermal energy through the entire metal structure, making metals good conductors of electricity and heat.

Most Metals Are Malleable

1. The layers of atoms in a metal can slide over each other, making metals malleable, meaning they can be bent, hammered, or rolled into flat sheets.

Alloys Are Harder Than Pure Metals

1. Pure metals are often too soft for certain jobs, so they are mixed with other metals to form alloys, which are harder and more useful.

2. Different elements have different sized atoms, so when another element is mixed with a pure metal, the new atoms distort the layers of metal atoms, making it harder for them to slide over each other. This makes alloys harder than pure metals.