chemical group vs methylene group

Other hyponyms of chemical group include acyl, acyl group, alcohol group, alcohol radical, aldehyde group, aldehyde radical, alkyl, alkyl group, alkyl radical, allyl, allyl group, allyl radical, amino, amino group, amyl, azido group, azido radical, azo group, azo radical, benzyl, benzyl group, benzyl radical, benzoyl group, benzoyl radical, arsenic group, cacodyl, cacodyl group, cacodyl radical, carbonyl group, carboxyl, carboxyl group, chromophore, cyanide group, cyanide radical, cyano group, cyano radical, glyceryl, hydrazo group, hydrazo radical, hydroxyl, hydroxyl group, hydroxyl radical, ketone group, methylene, methylene radical, propyl, propyl group, propyl radical, butyl, nitro group, nitrite, uranyl, uranyl group, uranyl radical, vinyl, vinyl group, vinyl radical.