AQA · GCSE · Chemistry
Course version: 8462 · Version from Sept 2018
Metals react with oxygen to produce metal oxides. The reactions are…
Full specification wording
Metal oxides: Metals react with oxygen to produce metal oxides. The reactions are oxidation reactions because the metals gain oxygen.
Many metals react with oxygen to form metal oxides.
Checked against the AQA 8462 specification (opens in a new tab) on .
- Point 1 of 2
Study notes
From the checked teaching notes for this specification point.
The idea
Many metals react with oxygen to form metal oxides. For example, magnesium burns in oxygen to form white magnesium oxide: 2Mg + O₂ → 2MgO. Iron reacts more slowly to form iron oxide, and copper reacts on heating to form black copper(II) oxide: 2Cu + O₂ → 2CuO. These are oxidation reactions because the metal atoms gain oxygen. In terms of electrons, the metal atoms also lose electrons to form positive ions, so oxidation can be described as gain of oxygen or loss of electrons. The product is a metal oxide, which is usually a solid at room temperature. The reaction may be vigorous for reactive metals and slower for less reactive metals, but the same pattern applies.
What earns the marks
- States that metals react with oxygen to produce metal oxides.
- Identifies the reaction as oxidation because the metal gains oxygen.
- Writes a balanced symbol equation for a metal reacting with oxygen, for example 2Mg + O₂ → 2MgO.
- Names the metal oxide formed from a given metal and oxygen reaction.
- Links oxidation to the metal gaining oxygen, and where relevant to the metal losing electrons to form positive ions.
Common mistakes and how to put them right
Saying the metal is reduced because it gains oxygen.
Put it right by stating that gaining oxygen is oxidation.
Writing an unbalanced equation such as Mg + O₂ → MgO.
Put it right by balancing to 2Mg + O₂ → 2MgO.
Confusing oxidation with combustion only.
Put it right by explaining that oxidation is gain of oxygen, which can occur when a metal reacts with oxygen even without a flame.
Exam tips
- Use the phrase 'gain of oxygen' when explaining why a metal reacting with oxygen is oxidation.
- Balance equations for metal oxide formation by checking that the number of each type of atom is the same on both sides.
- Include state symbols where they are known, for example 2Mg(s) + O₂(g) → 2MgO(s), to show the metal oxide is a solid.
Try the lesson
The start of the Metal oxides: Metals react with oxygen to produce metal oxides. The reactions are oxidation reactions because the metals gain oxygen. lesson, made from checked teaching notes for this specification point.
Have a go first
When magnesium burns in oxygen, a white powder forms. What is the name of this product?
Listen
Many metals react with oxygen to form metal oxides. For example, magnesium burns in oxygen to form white magnesium oxide: 2Mg + O₂ → 2MgO. Iron reacts more slowly to form iron oxide, and copper reacts on heating to form black copper(II) oxide: 2Cu + O₂ → 2CuO. These are oxidation reactions because the metal atoms gain oxygen. In terms of electrons, the metal atoms also lose electrons to form positive ions, so oxidation can be described as gain of oxygen or loss of electrons. The product is a metal oxide, which is usually a solid at room temperature. The reaction may be vigorous for reactive metals and slower for less reactive metals, but the same pattern applies. A strong answer earns marks for these points. States that metals react with oxygen to produce metal oxides. Identifies the reaction as oxidation because the metal gains oxygen. Writes a balanced symbol equation for a metal reacting with oxygen, for example 2Mg + O₂ → 2MgO. Names the metal oxide formed from a given metal and oxygen reaction. A common slip: Saying the metal is reduced because it gains oxygen. Instead, stating that gaining oxygen is oxidation. Exam tip: Use the phrase 'gain of oxygen' when explaining why a metal reacting with oxygen is oxidation.
See it
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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