A charged particle formed when an atom transfers electrons is called an ion.

Here's why:

* Atoms are electrically neutral because they have an equal number of protons (positively charged) and electrons (negatively charged).

* Ions are formed when an atom gains or loses electrons.

* Cations are positively charged ions formed when an atom loses electrons.

* Anions are negatively charged ions formed when an atom gains electrons.

Let me know if you'd like more details about ions!