# plasmapy.particles.atomic

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

## Functions

 atomic_number(element) Return the number of protons in an atom, isotope, or ion. charge_number(particle) 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. electric_charge(particle) 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. known_isotopes([argument]) 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. mass_number(isotope) 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. periodic_table_block(argument) Return the periodic table block. periodic_table_category(argument) Return the periodic table category. periodic_table_group(argument) Return the periodic table group. periodic_table_period(argument) 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. standard_atomic_weight(element) Return the standard (conventional) atomic weight of an element based on the relative abundances of isotopes in terrestrial environments.