Question

1. a student examined the chemical formula for a compound, $ce{h_{2}c_{6}h_{5}o_{7}}$. the compound contains all nonmetals, so the student classified the compound as a molecule. this classification is incorrect. how should the compound have been classified? ___________ why?_________

Explanation:

The formula $\text{H}_2\text{C}_6\text{H}_5\text{O}_7$ represents the hydrogen citrate ion (a polyatomic ion's protonated form), which is a cation-anion combination when paired with a cation, or it is an ionic compound component. Ionic compounds can consist of nonmetals (like polyatomic ions) and form charged species, not neutral molecules. This compound has a net charge (the formula corresponds to $\text{HC}_6\text{H}_5\text{O}_7^-$ plus an extra $\text{H}^+$, making it a charged species overall), so it is ionic, not a neutral molecular compound.

Answer:

Classification:

It should be classified as an ionic compound (specifically, the formula represents the hydrogen citrate species, which is part of ionic salts like sodium hydrogen citrate, or it is a charged polyatomic ion derivative that forms ionic compounds).

Reason:

The compound is a charged species (not a neutral molecule), and compounds containing charged polyatomic ions (even with only nonmetals) are ionic, not molecular. The formula $\text{H}_2\text{C}_6\text{H}_5\text{O}_7$ corresponds to a protonated form of the citrate ion, which carries a net charge, so it forms ionic bonds with oppositely charged ions rather than existing as a neutral covalent molecule.