What is a molecule?
In GCSE chemistry, a molecule is a group of two or more atoms chemically combined. Both elements and compounds can exist as molecules. For example, carbon dioxide is a compound and exists as molecules consisting of one carbon atom and two oxygen atoms, CO2. Hydrogen is an element and exists as molecules consisting of two hydrogen atoms, H2.
Molecules are usually formed from non-metal atoms. They are therefore held together by covalent bonds which involve the sharing of electrons. Substances that exist as molecules usually have low melting and boiling points. Although they have strong covalent bonds between the atoms, there are weak intermolecular forces between the molecules. These require little energy to overcome. Generally, as the size of the molecule increases, so does the melting / boiling point due to the strength of these forces increasing.
Molecule Revision Resources to Ace Your Exams
Most exam boards require you to give the formula of common molecules and explain the properties of simple molecules. To make sure you ace this topic in your exams, you can also practice our exam questions on bonding.
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Written by Alexandra Brennan
Chemistry 9 articlesAlex 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.
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