Ions
Chemistry: AQA GCSE Higher, topic 2.1.2
Ions
Ions are particles that have a charge. They are created when an atom or molecule gains or loses electrons. Gaining electrons creates a negatively charged ion; losing electrons creates a positively charged ion.
Positive ions (cations)
- Positive ions are usually created when an atom or molecule loses electrons.
- Positive ions are also called cations.
- The metals in Group 1 and 2 can easily lose electrons to become positively charged ions.
Negative ions (anions)
- Negative ions are usually created when an atom or molecule gains electrons.
- Negative ions are also called anions.
- The non-metals in Group 7 are most likely to gain electrons to fill up their electron shell and become negatively charged.
Ions containing multiple elements
- Ions can be made up of:
- 1 atom (e.g. F-).
- Combinations of atoms with an overall charge (e.g. SO42-).
Test yourself on Ions
Which of these elements would form a negatively charged ion?
If an atom loses electrons, what charge does the resulting ion have?
Why does a chlorine atom become a negative ion by gaining 1 electron?
An atom loses electrons to form an ion. What is this type of ion called?
How does the sulfate ion, SO42-, differ from the fluoride ion, F-, in the way it is formed?