Specific charge

The specific charge of a subatomic particle, nucleus or isotope is the ratio of its charge to its mass.

In other words, how much charge it has for every unit of mass.

Calculating specific charge

We can use this formula to calculate the specific charge of a particle, nucleus or isotope:

\text{Specific charge} = \frac{\text{Charge}}{\text{Mass}}

Sometimes, we represent specific charge as just \frac Qm because of its formula.

Where:

Because we are dividing charge (C) by mass (kg), our units are C\div kg\rightarrow C\,kg^{-1}

If you want the details of the different subatomic particles and their specific charges, see:

Otherwise, I’ve written a summary table below!

Particle	Charge (Q)	Mass (m)	Specific charge (\frac Qm)
proton	+1.6\times10^{-19}C	1.67\times10^{-27}kg	+9.58\times10^{7}C/kg
neutron	0	1.675\times10^{-27}kg	0
electron	-1.6\times10^{-19}C	9.11\times10^{-31}kg	-1.76\times10^{11}C/kg

Question	Answer
What is the specific charge of a subatomic particle, nucleus or isotope?	The ratio of its charge to its mass.
What is the formula for calculating specific charge?	\text{Specific charge} = \frac{\text{Charge}}{\text{Mass}} or just \frac Qm
What are the units of specific charge?	C\,kg^{-1} (coulombs per kilogram)
What is the specific charge of a proton?	+9.58\times10^{7}C/kg
What is the specific charge of a neutron?	0
What is the specific charge of an electron?	-1.76\times10^{11}C/kg
What are the charge and mass of a proton used to calculate its specific charge?	Charge: +1.6\times10^{-19}C, Mass: 1.67\times10^{-27}kg
What are the charge and mass of a neutron?	Charge: 0, Mass: 1.675\times10^{-27}kg
What are the charge and mass of an electron?	Charge: -1.6\times10^{-19}C, Mass: 9.11\times10^{-31}kg
How do you find the specific charge of a nucleus, atom or isotope?	See the nucleus specific charge note.