Question

how to calculate valency of a given substance?

Answer 1

The valency of an element can be calculated as:

i. Write down the electronic configuration of the element.

ii. If the number of electrons in the outer most shell is less than four, then the valency of the substance is the number itself.

iii. If the number of electrons is more than 4 but less than 8, then subtract the number by 4 to get the valency.

To calculate the valency of molecules with more than one element,

i.. Consider a molecule AB.

ii. Calculate the valency of both the elements, A and B.

iii. Subtract the two valencies to get the valency of the molecule.