Question

the electronic configuration of an element X is 2, 8, 8, 2.to which a. period and b.group of the modern periodic table does x belong ?state its valency justify your answer in each case​

Answer 1

a) atomic number is 20 representing element Calcium

belongs to 4th period 2a group..

2) its valency is 2.. becoz it can lose 2 electrons to gain octat.

Answer 2

Answer:

1 . Since ‘X’ has three energy shells and period number of an element is equal to the number  of energy shells, X belongs to 4rd period.

2 . X has 2 valence electrons it belongs to group 2.

3.  Valency will be 2. To acquire noble gas configuration it will gain 2 electrons.