chemistry

Reactivity of Metals The reactivity series is a list of metals arranged in order of their reactivity. The general order from most to least reactive is: (K) Potassium (Na) Sodium (Ca) Calcium (Mg) Magnesium

(Al) Aluminium (Zn) Zinc (Fe) Iron (Sn) Tin

(Pb) Lead (Cu) Copper (Ag) Silver (Au) Gold

More reactive metals lose electrons more easily to form positive ions. Less reactive metals do not react as vigorously or may not react at all. Gold and silver are very unreactive and found in their natural state. Reactions of Metals with Oxygen Metals react with oxygen to form metal oxides. Example: Magnesium + Oxygen → Magnesium Oxide 2Mg + O₂ → 2MgO Highly reactive metals (e.g., potassium, sodium) react rapidly. Less reactive metals (e.g., iron, copper) react slowly or only when heated.

Reactions of Metals with Water Very reactive metals (Potassium, Sodium, Calcium) react violently with water, producing hydrogen gas and metal hydroxides. Example: Potassium + Water → Potassium Hydroxide + Hydrogen 2K + 2H₂O → 2KOH + H₂ Less reactive metals (Magnesium, Zinc, Iron) react slowly or only with steam. Unreactive metals (Copper, Silver, Gold) do not react with water.

Reactivity and Rate of Reaction More reactive metals react faster. Less reactive metals react more slowly or not at all. Hydrogen gas test: Use a lit splint; a 'pop' sound confirms hydrogen is present.

Reactions of Acids with Metals Metals react with dilute acids to form salts and hydrogen gas. Observations: Bubbling/fizzing (hydrogen gas produced), metal disappears as it dissolves. General Equation: Metal + Acid → Salt + Hydrogen Examples: Magnesium + Hydrochloric Acid → Magnesium Chloride + Hydrogen Mg + 2HCl → MgCl₂ + H₂ Zinc + Sulfuric Acid → Zinc Sulfate + Hydrogen Zn + H₂SO₄ → ZnSO₄ + H₂ Naming Salts The type of acid used determines the salt formed: Hydrochloric acid (HCl) → Chloride salts (e.g., MgCl₂, ZnCl₂) Sulfuric acid (H₂SO₄) → Sulfate salts (e.g., MgSO₄, ZnSO₄) Nitric acid (HNO₃) → Nitrate salts (e.g., Mg(NO₃)₂, Zn(NO₃)₂)