Among the following elements, which one is not present in a pure sugar ?

Pure sugar, scientifically known as sucrose, is a carbohydrate. Carbohydrates are organic compounds defined by their composition of carbon (C), hydrogen (H), and oxygen (O) atoms [t1][t2]. The molecular formula for sucrose is C12H22O11, which explicitly shows it contains 12 carbon atoms, 22 hydrogen atoms, and 11 oxygen atoms [t5][t6]. The term 'carbohydrate' itself reflects this composition, derived from 'carbon' and 'hydrate' (water, H2O), typically following the general formula Cm(H2O)n [t2][t7]. Nitrogen is a vital nutrient for living organisms and has its own gaseous cycle, but it is not a constituent element of pure sugar molecules [c1]. While nitrogen is found in other biomolecules like proteins (amino acids) and nucleic acids, it is absent in the chemical structure of pure saccharides like glucose, fructose, and sucrose [t1][t3].

Sources

1. [1] https://www.sciencedirect.com/topics/neuroscience/carbohydrates
2. [2] https://www.khanacademy.org/science/ap-biology/chemistry-of-life/properties-structure-and-function-of-biological-macromolecules/a/carbohydrates
3. [3] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > Carbon and Oxygen Cycles > p. 19
4. [4] https://www.sciencedirect.com/science/article/abs/pii/S0043135417304256#!