Question

which two types of particles are present in equal numbers in an atom, but not in an ion? choose protons & electrons protons & neutrons inner - shell electrons and outer - shell electrons protons & inner - shell electrons

Explanation:

In a neutral atom, the number of protons (positively - charged particles) is equal to the number of electrons (negatively - charged particles), giving the atom a net charge of zero. In an ion, electrons are either gained or lost, so the number of protons and electrons is no longer equal. Protons and neutrons do not necessarily have equal numbers in atoms or ions. Inner - shell and outer - shell electrons don't have an equal - number relationship in the context of atoms and ions as described. And there is no such fixed equal - number relationship between protons and inner - shell electrons.

Answer:

protons & electrons