An atom with a different number of protons and electrons is called an ion.

Here's why:

* Protons: Determine the element. The number of protons in an atom's nucleus defines what element it is.

* Electrons: Carry a negative charge. They orbit the nucleus.

* Ions: When an atom gains or loses electrons, it becomes an ion.

* Cations: Positively charged ions are formed when an atom loses electrons (more protons than electrons).

* Anions: Negatively charged ions are formed when an atom gains electrons (more electrons than protons).

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