A cation is a positively charged ion formed when an atom loses electrons. Here are five examples of cations with explanations:

1. Sodium Ion (Na⁺)

• Formed when sodium (Na) loses one electron: Na→Na++e−Na \rightarrow Na^+ + e^-
• Charge: +1
• Example: Found in table salt (NaCl) and electrolytes in the body.

2. Calcium Ion (Ca²⁺)

• Formed when calcium (Ca) loses two electrons: Ca→Ca2++2e−Ca \rightarrow Ca^{2+} + 2e^-
• Charge: +2
• Example: Found in bones, teeth, and milk (as calcium salts).

3. Iron(II) Ion (Fe²⁺) and Iron(III) Ion (Fe³⁺)

• Iron(II) (Fe²⁺) is formed when iron loses two electrons: Fe→Fe2++2e−Fe \rightarrow Fe^{2+} + 2e^-
• Iron(III) (Fe³⁺) is formed when iron loses three electrons: Fe→Fe3++3e−Fe \rightarrow Fe^{3+} + 3e^-
• Charge: +2 or +3
• Example: Found in hemoglobin (Fe²⁺) and rust (Fe³⁺ oxides).

4. Hydrogen Ion (H⁺)

• Formed when hydrogen loses one electron: H→H++e−H \rightarrow H^+ + e^-
• Charge: +1
• Example: Found in acids (HCl, H₂SO₄) and fuels cell reactions.

5. Ammonium Ion (NH₄⁺)

• Formed by the addition of a hydrogen ion (H⁺) to ammonia (NH₃): NH3+H+→NH4+NH_3 + H^+ \rightarrow NH_4^+
• Charge: +1
• Example: Found in fertilizers and household cleaners.