aldehydes and ketones

Carbonyls are compounds with a C=O bond. They can be either aldehydes or ketones

Pure carbonyls cannot hydrogen bond to themselves, but are attracted instead by permanent dipole forces

The smaller carbonyls are soluble in water because they can form hydrogen bonds with water.

In comparison to the C=C bond in alkenes, the C=O is stronger and does not undergo addition reactions easily. The C=O bond is polarised because O is more electronegative than carbon. The positive carbon atom attracts nucleophiles. This is in contrast to the electrophiles that are attracted to the C=C .