What is the difference in the molecular formula of 2 successive members of the homologous series of a carbon additive?

A homologous series may be defined as a family of organic compounds having the same functional group, and the successive(adjacent) members of which differ by a CH
2

unit or 14 mass units.

Two consecutive members of homologous series of Aldehydes: CH
3

CHO and C
2

H
5

CHO

A carbon compound is made up of two parts: R−F, where R is the hydrocarbon part and F is the functional group part.
So, this R (hydrocarbon) part determines the physical properties of a compound and the F (functional group) part determines the chemical properties of the compounds.

C) electrons encircling a nucleus with neutrons and protons