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Explore the Chemical Formulae of Compounds

In this worksheet, students will explore the chemical formulae of compounds.

'Explore the Chemical Formulae of Compounds' worksheet

Key stage:  KS 3

Year:  Year 7 Science worksheets

Curriculum topic:   Chemistry: Atoms, Elements and Compounds

Curriculum subtopic:   Chemical Symbols and Formulae

Difficulty level:  

Worksheet Overview

Ethanol, steric acid, methanol...... all names of compounds.


Each compound has a unique chemical formula. It is made up of symbols and numbers. The symbols tell us which elements are in the compound, and the numbers tell us how many atoms of each element are in a molecule of the compound. 


Carbon dioxide has the formula:




This means there is 1 atom of carbon and 2 atoms of oxygen in each molecule of carbon dioxide.


molecules of carbon dioxide


We can apply the same principle to more complex compounds, but don't let the complexity get you confused!


MgSO4 contains three elements, Mg (magnesium), S (sulfur) and O (oxygen). The numbers tell us how many of each atom there are in a molecule of the compound, so in this case, as there is no number after Mg, we can tell there is only 1 atom present. The same goes for S. But there is a little 4 after O, so that tells us that there are 4 atoms of oxygen in a molecule of the compound.


By the way, the word 'formulae' is the plural of the word formula. If we're talking about more than one formula, we usually say formulae.


group of children thinking


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