Functions that retrieve or are related to elemental or isotopic data.



Return the number of protons in an atom, isotope, or ion.


Return the charge number of a particle.

common_isotopes([argument, most_common_only])

Return a list of isotopes of an element with an isotopic abundances greater than zero, or if no input is provided, a list of all such isotopes for every element.


Return the electric charge (in coulombs) of a particle.

half_life(particle[, mass_numb])

Return the half-life in seconds for unstable isotopes and particles, and inf seconds for stable isotopes and particles.

ionic_levels(particle[, min_charge, max_charge])

Return a ParticleList that includes different ionic levels of a base atom.

is_stable(particle[, mass_numb])

Return True for stable isotopes and particles and False for unstable isotopes.

isotopic_abundance(isotope[, mass_numb])

Return the isotopic abundances if known, and otherwise zero.


Return a list of all known isotopes of an element, or a list of all known isotopes of every element if no input is provided.


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

particle_mass(particle, *[, mass_numb, Z])

Return the mass of a particle.


Return the periodic table block.


Return the periodic table category.


Return the periodic table group.


Return the periodic table period.

reduced_mass(test_particle, target_particle)

Find the reduced mass between two particles.

stable_isotopes([argument, unstable])

Return a list of all stable isotopes of an element, or if no input is provided, a list of all such isotopes for every element.


Return the standard (conventional) atomic weight of an element based on the relative abundances of isotopes in terrestrial environments.