- An ion is an atom or group of atoms carrying a positive or negative charge. Example Ca2+, O2-, SO42- etc.
- If a particle has equal numbers of protons (+) and electrons (-), the particle charge is zero, and the particle is said to be neutral.
- In a chemical reaction, electron(s) can be transferred from atom to another atom.
- If electron(s) is removed from an atom, the number of protons will be more than the number of electrons. In this case, the atom will have excess positive charge and hence form a positive ion (cation).
|(An atom losses electron to form positive ion)|
- If an atom gains electrons, there is an excess negative charge in the atom, so a negative ion is formed.
- In other words,
- The atom losing electrons forms a positive ion (cation) and is usually a metal.
- The atom gaining electrons forms a negative ion (anion) and is usually a non-metallic element.
|(An atom gain electron to form negative ion)|
What are Ions | The Fuse School
What is an ion? What role does it have to play in the structure of atoms? Find out in this Chemistry Journey video by The Fuse School.