Question

Describe briefly the long form of the periodic table (5 marks)

Answer 1

The solution is as follows:

- Modern periodic table is made to arrange the elements in an order which is periodic function of their atomic numbers.
- There are 18 groups and 7 groups in the table.
- Elements across the period are arranged with increasing electrons in the same shell, and down the group are arranged with increasing shell having same number of valence electrons.
- Trends in modern periodic table:

- Valency: It first increases in the period then decreases and becomes 0 for group 18.
- Atomic Size: Across a period atomic size decreases and down the group atomic size increases.
- Metallic and Non-metallic character - Metallic character decreases across a period and non-metallic character increases. Metallic character increases down the group and non-metallic character increases.