# State the meaning of the formula MgCl₂ and describe what information the subscript '2' provides about the compound.

> Cambridge International IGCSE Chemistry (0620) — 3.1 Formulae · State · 4 marks

> Magnesium chloride has the formula MgCl₂.

## Mark scheme (4 marks)

1. The formula shows magnesium chloride contains magnesium and chlorine (atoms/elements)
2. The formula shows the ratio of atoms in the compound
3. The subscript '2' means there are two chlorine atoms for every one magnesium atom
4. MgCl₂ is the simplest / empirical formula showing the simplest whole-number ratio of atoms in the compound

## Key terms

- [formula](https://www.gradenine.co.uk/glossary/formula)
- [subscript](https://www.gradenine.co.uk/glossary/subscript)

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