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Glossary

Compound: GCSE Chemistry Definition

Alexandra Brennan

Written by: Alexandra Brennan

Reviewed by: Stewart Hird

Published

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2 minutes

Contents

  1. 1. What is a compound?
  2. 2. Compound Revision Resources to Ace Your Exams

What is a compound?

In GCSE chemistry, a compound consists of two or more elements chemically combined. Compounds form when elements take part in chemical reactions. Examples of compounds include carbon dioxide, sodium chloride and water. 

Diagram of three molecules: Sodium Chloride (NaCl), Water (H2O), Carbon Dioxide (CO2) with respective ball-and-stick models.
Compounds are made up of two different elements chemically combined

The chemical formula of a compound can tell us the number of each type of atom. For example, the formula of sodium chloride, NaCl, tells us that there is one sodium and one chlorine atom.  Water, H2O, has two hydrogen atoms and one oxygen atom. Carbon dioxide, CO2, has two oxygen atoms and one carbon atom, 

Compounds often have very different properties to the elements they are made up from. Sodium chloride is a white crystalline solid, but is formed from sodium, a soft grey solid, and chlorine, a green gas. 

Diagram showing a chemical reaction: sodium (grey solid) and chlorine (green gas) form sodium chloride (white crystalline solid).
The properties of sodium, chlorine and sodium chloride

Naming compounds depends on the elements present. If the compound contains a metal and non-metal, then the non-metal element takes on the name ending ‘-ide’.  Some examples include, magnesium bromide, potassium chloride, lithium oxide. If oxygen is present in addition to a metal and non-metal, the compound takes on the name ending ‘-ate’. For example, a compound containing magnesium, bromine and oxygen would be called magnesium bromate. 

Compound Revision Resources to Ace Your Exams

Our Save My Exams revision notes on compounds will enhance your understanding on how compounds are formed and details on how to name them. Apply this knowledge to our atomic model exam questions. The flashcards are perfect for testing your knowledge of key terms, helping you remember important details and feel more prepared for exams

Explore Our GCSE Chemistry Revision Resources

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Author
Reviewer
Alexandra Brennan

Author: Alexandra Brennan

Expertise: Chemistry

Alex studied Biochemistry at Newcastle University before embarking upon a career in teaching. With nearly 10 years of teaching experience, Alex has had several roles including Chemistry/Science Teacher, Head of Science and Examiner for AQA and Edexcel. Alex’s passion for creating engaging content that enables students to succeed in exams drove her to pursue a career outside of the classroom at SME.

Stewart Hird

Author: Stewart Hird

Expertise: Chemistry Lead

Stewart has been an enthusiastic GCSE, IGCSE, A Level and IB teacher for more than 30 years in the UK as well as overseas, and has also been an examiner for IB and A Level. As a long-standing Head of Science, Stewart brings a wealth of experience to creating Topic Questions and revision materials for Save My Exams. Stewart specialises in Chemistry, but has also taught Physics and Environmental Systems and Societies.

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