Introduction

Elements are classified into two basic categories, metals and non-metals.

There are about 90 elements, up to Uranium, that are found naturally. Another 20 elements, beyond Uranium, called trans-uranium elements, have been produced artificially in the laboratories by nuclear reactions. Two elements, Technetium (Tc) and Promethium (Pm) that occur below Uranium are unstable in nature. Elements can be classified by the physical and chemical properties that they display

Metals are defined as those elements which possess lusture, are malleable and ductile and good conductors of heat and electricity.

Or

Metals are the elements which form positive ions by losing electrons i.e. they are electropositive elements.

For e.g. sodium, magnesium, potassium, aluminium, copper, silver, gold etc.

Non-metals are defined as those elements which do not possess lusture and are neither good conductors of heat and electricity nor malleable. They are not ductile but are brittle.

Or

Non-metals are the elements which form negative ions by gaining electrons i.e. they are electronegative elements.

For e.g. carbon, hydrogen, oxygen, nitrogen, sulphur, bromine etc.

What we will study in this chapter :

• Physical and chemical properties of non-metals
• Electronic configuration of metals and non-metals
• Reactivity series of metals
• Comparison between metals and non-metals
• Study of some metals
• Metallurgy : extraction of ores and refining of ores