mass_number

plasmapy.particles.atomic.mass_number(isotope: str | int | integer | Particle | CustomParticle | Quantity) → int

Get the mass number (the number of protons and neutrons) of an isotope.

Parameters:

isotope (atom-like) – A string representing an isotope or a neutron; or an instance of the plasmapy.particles.particle_class.Particle class.

Returns:

The total number of protons plus neutrons in a nuclide.

Return type:

int

Raises:

• InvalidParticleError – If the argument does not correspond to a valid particle.

• InvalidIsotopeError – If the argument does not correspond to a valid isotope.

See also

atomic_number

Examples

>>> mass_number("H-1")
1
>>> mass_number("Pb-208")
208
>>> mass_number("tritium")
3
>>> mass_number("alpha")
4