Metallic bonding

Metals

• Metals have a giant metallic structure.

• There are strong electrostatic forces of attraction between the fixed metal cations amid the sea of (delocalised) mobile electrons

• The metal cations are held in fixed positions in a lactic structure by the strong electrostatic forces of attraction.

Physical properties of metal

1. Metals have a high melting and boiling points (except grp 1 metals) : Metals have giant lattice structures with strong electrostatic forces of attraction between the fixed metal cations and the sea of mobile electrons, which require a lost of energy to overcome thus metals have high melting and boiling points.

2. Metals can conduct heat and electricity: Metals have free mobile electrons to carry charges and transfer heat.

3. Metals are malleable and ductile: In pure metals, the metal atoms are the same size and they are arranged in an orderly manner, thus the layers of metal atoms can slide past easily when a force is applied, making metals ductile and malleable.

4. Metals have high densities: The metal atoms are closely packed together, hence they are many atoms per unit volume, resulting in high densities.

Alloy

An alloy is a mixture of a metal with one or more elements

Physical properties of Alloys

Since different elements are present in an alloy, the size of the atoms are also different. The atoms of the added elements disrupts the orderly arrangement of the layers of atom due to their different sizes, making it difficult for the layers of the atoms to slide past one another. Thus alloys are harder and stronger than pure metals.