# Calcium chloride has the formula CaCl₂. Hydrogen chloride has the formula HCl. Explain the difference between a compound and an element, and state whether calcium chloride and hydrogen chloride are the same type of compound. Give a reason for your answer.

> Pearson Edexcel International GCSE Chemistry (4CH1) — 1.5 Chemical formulae, equations and calculations · Explain · 4 marks

> Calcium is a metal in Group 2 of the periodic table. Chlorine is a non-metal in Group 7. Hydrogen chloride is a gas at room temperature.

## Mark scheme (4 marks)

1. A compound is a substance made up of two or more types of atoms chemically combined together
2. Both calcium chloride and hydrogen chloride are compounds (not elements)
3. Both substances contain more than one type of atom chemically combined / both contain two different elements
4. Calcium chloride is an ionic compound (formed between a metal and a non-metal / contains an ionic bond) whereas hydrogen chloride is a covalent compound (formed between two non-metals / contains a covalent bond), so they are different types of compound

## Key terms

- [compound](https://www.gradenine.co.uk/glossary/compound)
- [element](https://www.gradenine.co.uk/glossary/element)

## Related

- [Revision notes for Pearson Edexcel International GCSE Chemistry (4CH1)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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