Question

Write the electronic configuration of each one of Li (3), Na (11) and K (19) and answer the following question:

Formula of sodium sulphate is ${\mathrm{Na}}_2{\mathrm{SO}}_4$. Write the formula of potassium sulphate.

Answer 1

Step-1: Introduction

The elements in periodic table are placed in periods and groups. Periods are horizontal rows that has increasing atomic numbers. Groups are vertical columns. There are 7 periods and 18 groups in periodic table.

Step-2: Electronic configuration

Atomic numbers of Lithium ($\mathrm{Li}$), Sodium ($\mathrm{Na}$) and Potassium ($\mathrm{K}$) are 3, 11 and 19 respectively.

Electronic configuration of Lithium = (2, 1).

Electronic configuration of Sodium = (2, 8, 1).

Electronic configuration of Potassium = (2, 8, 8, 1).

All these elements belong to group 1.

Step-3:

${\mathrm{Na}}_2{\mathrm{SO}}_4$ is formula of Sodium sulphate.

Therefore, the formula of Potassium sulphate is ${\mathrm{K}}_2{\mathrm{SO}}_4$.