* Neutral Atoms: Atoms in their natural state have an equal number of protons (positively charged particles) and electrons (negatively charged particles). These opposite charges cancel each other out, making the atom electrically neutral.

* Ions: When an atom gains or loses electrons, it no longer has an equal number of protons and electrons. This creates an imbalance in charge, making the atom an ion:

* Cations: Atoms that lose electrons become positively charged ions (cations).

* Anions: Atoms that gain electrons become negatively charged ions (anions).

Examples:

* A sodium atom (Na) has 11 protons and 11 electrons. If it loses one electron, it becomes a sodium ion (Na+) with a +1 charge.

* A chlorine atom (Cl) has 17 protons and 17 electrons. If it gains one electron, it becomes a chloride ion (Cl-) with a -1 charge.

Key takeaway: The gain or loss of electrons determines the charge of an atom.