Ions are formed when atoms a) gain or lose protonsb) gain or lose electronsc) gain or lose neutrons d) each of these results in ion formatione) none of these results in ion formation

b) Gain or lose electrons

Explanation:

An ion is an electrically charged particle. For an atom to be charged, it must have gained or lost electron in the process and therefore, it becomes an ion.

The loss or gain of electrons is what makes an atom charged and eventually becomes an ion.

A positively charged ion is one that has lost an electron and it is called a cation. In such an ion, the number of electrons are lesser than those of protons. This is why they are cations

A negatively charged ion is one that has gained electrons. They are called anions. In such an ion, the number of electrons are greater than that of protons.