Question

If atomic mass of one of element of homologos series is 98u what will be the atomic mass of previous number?

Answer 1

In homologous series the two consecutive members will differ by 14u or CH2 units

In case of alkanes (General Formula : CnH2n+2)

Example methane and ethane.

CH4 , C2H6, C3H8

Molecules masses are 16, 30, 44

Consecutive ones differ by 14.

And each differ by -CH2 units.