Carbohydrates are composed of three primary elements: carbon (C), hydrogen (H), and oxygen (O). The typical elemental ratio is about 1 carbon to 2 hydrogens to 1 oxygen, often summarized as roughly C:H:O = 1:2:1, and many carbohydrates have the empirical formula (CH2O)n. Monosaccharides are the simplest units (e.g., glucose, C6H12O6), which can form disaccharides and polysaccharides through glycosidic bonds. The atoms that make up carbohydrates are therefore C, H, and O in those proportions, organized into various saccharide structures. If you’d like, I can tailor this to a specific carbohydrate (glucose, sucrose, starch, cellulose) and show its exact chemical formula and structure.