1. Specific Charge of a Particle
The specific charge carried by a sub atomic particle or nucleus is a measure of how “densely charged” it is.
Specific charge (Ckg-1)= charge on the particle (C)
mass of the particle (kg)
Q is the symbol generally used for charge and m for mass so:
Specific charge =

2. The specific charge of the electron
The specific charge of the proton

3. Each proton carries a charge of 1.6 X 10 -19C
To calculate the specific charge of a nucleus e.g. helium, we need to know its mass and the charge it carries: +
The helium nucleus is composed
of 2 protons and 2 neutrons
Each proton carries a charge of 1.6 X C
So its overall charge in coulombs is 2 x 1.6 x 10-19C = 3.2 x 10-19C
The mass of a nucleon is 1.67 x 10-27kg
So its total mass is 4 x 1.67 x 10-27kg = 6.68 x 10-27kg
Now apply the formula
Specific charge =

4. Calculate the specific charge on each of the nuclei below

5. Isotopes Calculate the specific charge on each pair of isotopes.
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