About Metals and Non-Metals

The IGCSE spec. states you have to recall the positions of metals and non-metals on the periodic table. That’s easy! Its on page two. Have a look. Its colour-coded.

Anyways, this section covers 2.2, 2.3 and 2.5.

Metals

Metals tend to be shiny. They tend to have high melting and boiling points because of powerful attractions. Metals conduct heat and electricity because delocalized electrons are free to move throughout the structure. Metals are usually easy to shape due to their regular packed molecules. Metals react with water to form bases, and their oxides are also bases. They are good reducing agents because they lose electron.

Non-Metals

Non-metals tend to be brittle. They are poor conductors of heat and electricity. They form acidic oxides and are good oxydising agents because they gain electrons.

Aluminium Oxide

Aluminium oxide is amphoteric. It can neutralize both an acid and a base.

Reaction with acids

Aluminium oxide contains oxide ions and so reacts with acids in the same way as sodium or magnesium oxides. That means, for example, that aluminium oxide will react with hot dilute hydrochloric acid to give aluminium chloride solution.

In this (and similar reactions with other acids), aluminium oxide is showing the basic side of its amphoteric nature.

Reaction with bases

Aluminium oxide has also got an acidic side to its nature, and it shows this by reacting with bases such as sodium hydroxide solution. Various aluminates are formed – compounds where the aluminium is found in the negative ion. This is possible because aluminium has the ability to form covalent bonds with oxygen.