Question

write the electronic configuration of an element whose mass number is 31 and atomic number is 15. what is it valency.

Answer 1

Given:

Mass number = 31

Atomic number = 15

To find:

The electronic configuration and valency.

Solution:

Electronic configuration = ( 2, 8, 18, 32, ... )

Here,

The atomic number = 15

And so,

Electronic configuration = ( 2, 8, 5 )

The third shell can occupy 8 electrons or 18 electrons.

Hence, the element needs 3 more electrons to fill the third shell.

Therefore, valency = 3.

Answer 2

given , mass no.= 31

atomic no.= 15

electronic configuration:- 2,8,5

valency = 3