AQA · GCSE · Chemistry
Course version: 8462 · Version from Sept 2018
Positively charged ions move to the negative electrode (the cathode), and…
Full specification wording
The process of electrolysis: Positively charged ions move to the negative electrode (the cathode), and negatively charged ions move to the positive electrode (the anode).
During electrolysis, oppositely charged ions are attracted to the electrodes.
Checked against the AQA 8462 specification (opens in a new tab) on .
- Point 4 of 7
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
During electrolysis, oppositely charged ions are attracted to the electrodes. Positively charged ions, called cations, move to the negative electrode, which is the cathode. Negatively charged ions, called anions, move to the positive electrode, which is the anode. For example, in molten lead bromide, Pb²⁺ ions move to the cathode and Br⁻ ions move to the anode. At the electrodes, the ions gain or lose electrons and form neutral products. Remembering that cations go to the cathode and anions go to the anode helps avoid confusion. The names cathode and anode are fixed by the polarity of the electrodes, not by the direction of ion charge.
What earns the marks
- Positively charged ions are attracted to the negative electrode, called the cathode.
- Negatively charged ions are attracted to the positive electrode, called the anode.
- The terms cathode and anode refer to the negative and positive electrodes respectively.
- At the electrodes, ions gain or lose electrons to form neutral products.
- A named example such as molten lead bromide can show Pb²⁺ ions moving to the cathode and Br⁻ ions moving to the anode.
Common mistakes and how to put them right
Mixing up the electrodes and sending positive ions to the anode.
Put it right: Positive ions move to the cathode.
Thinking that cathode means positive electrode.
Put it right: The cathode is the negative electrode.
Believing that ions change into electrons at the electrodes.
Put it right: Ions gain or lose electrons to form neutral atoms or molecules.
Exam tips
- Use the spelling link that cations are positive and go to the cathode.
- State the polarity of each electrode whenever you name the cathode or anode.
- Support your answer with a named electrolyte and the formulas of the ions moving to each electrode.
Try the lesson
The start of the The process of electrolysis: Positively charged ions move to the negative electrode (the cathode), and negatively charged ions move to the positive electrode (the anode). lesson, made from checked teaching notes for this specification point.
Have a go first
To which electrode do positively charged ions move during electrolysis?
Listen
During electrolysis, oppositely charged ions are attracted to the electrodes. Positively charged ions, called cations, move to the negative electrode, which is the cathode. Negatively charged ions, called anions, move to the positive electrode, which is the anode. For example, in molten lead bromide, Pb²⁺ ions move to the cathode and Br⁻ ions move to the anode. At the electrodes, the ions gain or lose electrons and form neutral products. Remembering that cations go to the cathode and anions go to the anode helps avoid confusion. The names cathode and anode are fixed by the polarity of the electrodes, not by the direction of ion charge. A strong answer earns marks for these points. Positively charged ions are attracted to the negative electrode, called the cathode. Negatively charged ions are attracted to the positive electrode, called the anode. The terms cathode and anode refer to the negative and positive electrodes respectively. At the electrodes, ions gain or lose electrons to form neutral products. A common slip: Mixing up the electrodes and sending positive ions to the anode. Instead, positive ions move to the cathode. Exam tip: Use the spelling link that cations are positive and go to the cathode.
See it
Key words
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Cathode
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Anode
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Cations
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Anions
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See every definition
- Cathode
- The negative electrode, to which positively charged ions move during electrolysis.
- Anode
- The positive electrode, to which negatively charged ions move during electrolysis.
- Cations
- Positively charged ions, which move to the negative electrode, the cathode.
- Anions
- Negatively charged ions, which move to the positive electrode, the anode.
Label the diagram
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1Box 1
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3Box 3
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