Question

A and B are two metals with atomic no. 11 and 13 respectively. find their valency

Answer 1

Let's write their electronic configuration.

A --> 2 , 8 ,1 = 10
B --> 2,8,3 = 13

Number of valence electrons in A = 1
Number of valence electrons in B = 3

So valency is the number of valence electrons that has to be removed or gained to achieve inert gas electronic configuration

Valency of A = 1
Valency of B = 3

A will lose 1 electron to achieve stability while B will lose 3 electrons to achieve the same

Hope This Helps You!

Answer 2

atomic no. of A=11(sodium)
atomic no. of B=13(aluminium)
electronic configuration of sodium=2,8,1
sodium has 1 electron in its valence shell so it's valency is 1.

electronic configuration of aluminium=2,8,3
aluminium has 3 electrons in its valence shell so it's valency is 3.

A will lose 1 electron to complete it's octet.
B will lose 3 electrons to complete its octet.

valency of A=1
valency of B= 3.