Question

3rd period elements are called typical elements. Give reason.

Answer 1

Hint: Typical elements are the elements which can tell us about the properties of other elements belonging to their group. They are also called representative elements.

Complete step by step solution:
> The third period elements are called typical elements or representative elements because they represent the properties of their own group without anomalies.
 The third period consists of eight elements which are: sodium, magnesium, aluminium, silicon, phosphorus, sulfur, chlorine, and argon. The first two of these, sodium and magnesium, are members of the s-block, while the others are members of the p-block of the periodic table.
> The chemical properties and physical properties of all the elements of a group can be studied by studying these properties of the representative element of that group.
> If we want to study the properties of group 1, then you must better choose sodium and you get the clue about behaviour of other elements of its family.

Note: The elements of the 2nd period are not called typical elements because they show differences in properties with the properties of other elements in the same group. Some of the reasons for differences in their periodic properties and hence in their chemical behaviour are:
1. Small size of these elements
2. High electronegativity
3. Large charge/radius ratio