Image result for Which hydrogen is an unsaturated hydrocarbon ?
Alkenes have the general formula CnH2n, and are examples of unsaturated hydrocarbons. The presence of a double bond compound's structure causes there to be two fewer hydrogen atoms in the molecule than there are in an alkane with the same number of carbon atoms.
As you move across a period, the atomic mass increases because the atomic number also increases. ... The atomic mass for any given atom mainly comes from the mass of the protons and neutrons.
