Reactivity of metals

Chemical Reactions

• New substances formed in chemical reactions.

Reactivity of Metals

• Reactivity describes how readily a substance participates in reactions.

• Sodium: Very reactive; must be kept in oil to prevent reaction with water and air.

• Soft metal; tarnishes quickly when exposed to air.

Metal Reactions with Oxygen

• General equation: Metal + Oxygen = Metal Oxide.

• Sodium + Oxygen = Sodium Oxide (produces white powder).

• Copper: Forms black powder when heated, no flame.

• Iron: Forms rust (new substance) slowly in air.

Metal Reactions with Water

• Calcium: Sinks; reacts with water to produce hydrogen bubbles (calcium hydroxide).

• Sodium: Floats; reacts vigorously, producing hydrogen and bursts into flame.

• Iron: Sinks; no reaction with water.

• Magnesium: Reacts slowly, forming magnesium hydroxide.

General Reaction Equations

• Metal + Water = Metal Hydroxide + Hydrogen.

• Metal + Hydrochloric Acid = Metal Chloride + Hydrogen.

Collecting Hydrogen Gas

• Use a test tube to collect gas produced in reactions.

• Ensure to let air escape before measuring volume of gas collected.

Reactivity Series of Metals

• Ranked from most to least reactive:
    - Potassium, Sodium, Calcium, Magnesium, Zinc…
    - Iron, Copper, Silver, Gold (less reactive).

• Unreactive substances = Inert substances.

Strong Acids

• Example: Fluoroantimonic acid is extremely corrosive, reacts violently with water, requires special containers.