AQA · GCSE · Chemistry
Course version: 8462 · Version from Sept 2018
Elements that do not form positive ions are non-metals.
Full specification wording
Metals and non-metals: Elements that do not form positive ions are non-metals.
Non-metals are elements that do not form positive ions.
Checked against the AQA 8462 specification (opens in a new tab) on .
- Point 2 of 6
- 3 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Non-metals are elements that do not form positive ions. Instead, when they react they gain electrons to form negative ions, or they share electrons in covalent bonds. For example, chlorine gains one electron to form Cl⁻, and oxygen gains two electrons to form O²⁻. This happens because non-metals have relatively full outer shells, so gaining electrons is energetically favourable and gives a stable arrangement. The resulting negative ion has more electrons than protons. In reactions with metals, non-metals accept the electrons that metals lose, forming ionic compounds. Some non-metals, such as carbon and hydrogen, mainly form covalent bonds rather than ions, but they still do not form positive ions in these reactions.
What earns the marks
- State that non-metals do not form positive ions.
- Give an example such as Cl⁻ or O²⁻ with the correct charge.
- Explain that non-metal atoms gain electrons to form negative ions.
- Link electron gain to the outer-shell electron arrangement of non-metals.
- Describe electron transfer from a metal to a non-metal in a reaction such as sodium with chlorine.
Common mistakes and how to put them right
Writing ion charges without superscript signs.
Put it right by using forms such as Cl⁻ and O²⁻.
Saying all non-metals form negative ions.
Put it right by noting that some share electrons in covalent bonds.
Confusing non-metal ions with metal ions.
Put it right by checking whether the element is on the right of the periodic table.
Exam tips
- Use the phrase do not form positive ions to match the statement directly.
- Give one ionic example and one covalent example to show the range of non-metal behaviour.
- Check the charge sign and number when writing ions such as O²⁻.
Try the lesson
The start of the Metals and non-metals: Elements that do not form positive ions are non-metals. lesson, made from checked teaching notes for this specification point.
Have a go first
Which type of ion is formed by a non-metal when it reacts?
Listen
Non-metals are elements that do not form positive ions. Instead, when they react they gain electrons to form negative ions, or they share electrons in covalent bonds. For example, chlorine gains one electron to form Cl⁻, and oxygen gains two electrons to form O²⁻. This happens because non-metals have relatively full outer shells, so gaining electrons is energetically favourable and gives a stable arrangement. The resulting negative ion has more electrons than protons. In reactions with metals, non-metals accept the electrons that metals lose, forming ionic compounds. Some non-metals, such as carbon and hydrogen, mainly form covalent bonds rather than ions, but they still do not form positive ions in these reactions. A strong answer earns marks for these points. State that non-metals do not form positive ions. Give an example such as Cl⁻ or O²⁻ with the correct charge. Explain that non-metal atoms gain electrons to form negative ions. Link electron gain to the outer-shell electron arrangement of non-metals. A common slip: Writing ion charges without superscript signs. Instead, using forms such as Cl⁻ and O²⁻. Exam tip: Use the phrase do not form positive ions to match the statement directly.
See it
Key words
Say what each word means before you turn the card.
Non-metals
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Covalent bonding
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Electron transfer
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See every definition
- Non-metals
- Elements that do not form positive ions.
- Covalent bonding
- A way in which some non-metals share electrons rather than forming ions.
- Electron transfer
- The process in which non-metals accept the electrons that metals lose, forming ionic compounds.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
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