Since monosaccharides are the simplest units of carbohydrates, then they are made up of carbon, hydrogen, and oxygen atoms.
empirical formula : CxH2xOx
where
[tex]x \geqslant 3[/tex]
Monosaccharides can be classified by the number x of carbon atoms they contain: triose(3) tetrose (4), pentose (5), hexose (6), heptose (7), and so on.