Formula Builder & Practice
Learn, practise and test your knowledge of ionic and molecular formulae.
Ionic Formulae
Molecular Formulae
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Positive ion
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Negative ion
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Build this ionic compound
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Step 1 — Identify the ions
Positive ion
Ion formula
Charge
1
2
3
4
Sign
+
−
Negative ion
Ion formula
Charge
1
2
3
4
Sign
−
+
Check ions
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Step 2 — Build the compound
Compound formula
Type ordinary numbers. For example: Al2(SO4)3
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Choose different ions
Test question 1 of 10
Write the formula
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Next question
Choose a substance
Substance name
Write the molecular formula
Formula
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Practise question
Formula
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Next question
Test question 1 of 10
Write the formula
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