Question

write down the features of homologus series

Answer 1

The compounds in a homologous series should have 
1) similar chemical formulas 
2) similar chemical properties 
3) physical properties that show a gradual change or trend based on the differences in their formulas 

For example, you could look at boiling points of H2O, H2S, and H2Se and then explain the difference with a discussion of intermolecular forces.