Final answer:
Glucose is a carbohydrate molecule smaller than iodine, which is a larger halogen element. Glucose's size can be compared to other molecules by molar mass, and iodine's size can be understood by atomic radii trends.
Step-by-step explanation:
Glucose is a carbohydrate with the molecular formula C6H12O6, which is smaller than iodine, a halogen element represented by the symbol I. The size of a glucose molecule can be estimated when comparing it to other molecules using molar mass as a determining factor. Iodine, being an element, has an atomic radius that can be seen in a visual representation comparing it to other halogens. Typically, the atomic radii of elements increase as you move down a group in the periodic table due to the addition of electron shells.
To determine the exact size of the substance glucose, various methods can be applied, such as using membranes with different pore sizes. The method of determining molar mass is also reliable for comparing the sizes of substances such as glucose and sucrose. It is important to note that it's unsafe to taste chemicals to distinguish them.
Based on the trend in atomic sizes within a group on the periodic table, iodine, which is lower in its group than bromine, tends to be larger. The three factors that determine the trend of atomic size going down a group are the number of electron shells, effective nuclear charge, and electron-electron repulsion within the atom.