Which term tells the type and number of atoms in a substance?

Which term tells the type and number of atoms in a substance?

• A. Empirical formula
• B. Molecular formula
• C. Simple formula
• D. Chemical formula

Answer: (C)

The main idea here is how formulas represent what a substance is made of. A chemical formula can be written in different ways to show composition: the simplest way to describe what kinds of atoms are present and in what proportions is the simple (often called empirical) formula. This shows the types of atoms and their smallest whole‑number ratio, giving the basic building blocks that make up the substance. It doesn’t tell you exactly how many atoms are in one molecule—that would be given by the molecular formula, which can be a multiple of the simple formula. The general term for any notation of a compound’s composition is the chemical formula. In GCSE language, the simple formula is used to express the same idea as the empirical formula, so it’s the best fit for describing the kinds of atoms and their simplest ratio in a substance.

The main idea here is how formulas represent what a substance is made of. A chemical formula can be written in different ways to show composition: the simplest way to describe what kinds of atoms are present and in what proportions is the simple (often called empirical) formula. This shows the types of atoms and their smallest whole‑number ratio, giving the basic building blocks that make up the substance. It doesn’t tell you exactly how many atoms are in one molecule—that would be given by the molecular formula, which can be a multiple of the simple formula. The general term for any notation of a compound’s composition is the chemical formula. In GCSE language, the simple formula is used to express the same idea as the empirical formula, so it’s the best fit for describing the kinds of atoms and their simplest ratio in a substance.