Stoichiometry

• Group I: Valency = 1
• Group II: Valency = 2
• Group III: Valency = 3
• Group IV, Valency = +/-4
• Group V, Valency = -3
• Group VI, Valency = -2
• Group VII, Valency = -1
• Group VIII, Valency = 0
• Name: Iron

  Formula: $Fe^{2+}$

  Valency: +2
• Name: Copper (II)

  Formula: CU^{2+}

  Valency: +2
• Name: Copper

  Formula: $Cu^{2+}$

  Valency: +2
• Name: Ammonium

  Formula: $NH^{4+}$

  Valency: +4
• Name: Nitrate

  Formula: $NO_3$

  Valency: -1
• Name: Hydroxide

  Formula: OH-

  Valency: -1
• Name: Carbonate

  Formula: $CO3^{2-}$

  Valency: -2
• Name: Sulphate

  Formula: $SO4^{2-}$

  Valency: -2
• Name: Silicate

  Formula: SiO3 $^{2-}$

  Valency: -2
• Name: Phosphate

  Formula: PO4 $^{3-}$

  Valency: -3