mass_number

plasmapy.particles.mass_number(isotope: plasmapy.particles.particle_class.Particle) → numbers.Integral

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

Parameters

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

Returns

mass_number – 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.

• TypeError – The argument is not a str.

See also

atomic_number

returns the number of protons in an isotope or element

Examples

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