Positive ions (cations)
Na⁺ sodium, K⁺ potassium, Ca²⁺ calcium, Mg²⁺ magnesium, Al³⁺ aluminum, Fe²⁺ iron(II), Fe³⁺ iron(III), Cu²⁺ copper(II), NH₄⁺ ammonium.
Negative ions (anions)
Cl⁻ chloride, Br⁻ bromide, I⁻ iodide, F⁻ fluoride, O²⁻ oxide, S²⁻ sulfide, OH⁻ hydroxide.