I/GCSE Chemistry - Metal properties and reactivity

• Metals are important elements that are generally used as good conductors of heat and electricity
• Reactivity of metals is taught in GCSE Chemistry unit 10
• Major properties of metals include high melting points, conductors of electricity/heat, high density, malleable, ductile

Reactivity of metals

Metals react with air (oxygen)

• Metals react with oxygen to produce metal oxides
• They are oxidation reactions as oxygen is gained
• General formula: nM(s) + xO2 (g) --> M_nO_x (s)

Metals react with water/steam

• Metals more reactive than copper react with water to form metal hydroxide + hydrogen
• Metals less reactive than (/including)copper DOES NOT REACT with water/steam
• General formula: nM(s) + xH₂O (aq) --> M_nOH_X (s) + H₂ (g)
• Group I metals react vigorously with cold water
• e.g. Sodium, Lithium, Potassium, Calcium
• Group II/Transition metals react with steam
• e.g. Magnesium, Aluminum, Zinc, Iron, Lead

Metals react with diluted acid

• Metals react with acid to give out hydrogen gas
• General formula: M(s) + HCl/HNO₃/H₂SO₄ (aq) --> MX (s) + H₂ (g)
• Observation: bubbling/ colorless gas bubbles forms
• CAUTION: Group I metals react violently with acid!!

Reactivity series

• Metals react with other substances to form positive ions(anion)
• Metals lose their outermost shell electrons to other atoms
• Meaning that reactivity of a metal = the ease of losing electrons

Displacement reactions

Definition:

a more reactive metal takes the place of another metal(Positive charged ion) in a compound

• Examples: Zinc/magnesium/Iron react with acid
• Metal displaces hydrogen ion
• Zn (s) + H₂SO₄ (aq) --> ZnSO₄ (aq) + H₂ (g)
• Mg (s) + HCl (aq) --> MgCl (aq) + H₂ (g)
• Reactivity: Mg > Zn > H

Displacement reactions of metal oxides

• Examples:  Magnesium/lead react with metal solutions
• Mg (s) + AgNO₃ (aq) --> MgNO₃ (aq) + Ag (s) (no color change)
• Pb (s) + CuSO₄ (aq) --> PbSO₄ (aq) + Cu (s) (pale blue --> colorless)
• Pay attention to color change in solution

Extraction of metals

• Ores are rocks found on earth surface that contain enough metal to make it economical to extract the metal

Physical method:

Panning

• Metals that are natural occurring on earth/ can be mined directly
• Gold, Silver, Platinum

Chemical methods:

Direct combustion

• Less reactive metals that can be extracted by direct burning with oxygen in air
• Copper, Lead

Carbon reduction

• Metals less reactive than carbon can be extracted from their oxides by reduction with carbon
• Usually transition metals like Zinc, Iron, Tin
• For example, the extraction of copper using carbon reduction
•  2CuO (s) + C(s) --> 2Cu (s) + CO₂ (g)
• The copper oxide has lost oxygen (reduction)
• The carbon has gained oxygen (oxidation)

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Image references:

• Reactivity series of metals - http://onelearningsolution.blogspot.com/2015/02/33-reactivity-series-of-metals-and-its.html
• Displacement Reaction - http://www.chemistryland.com/CHM130FieldLab/Lab8/

Drafted by Yoyo (Chemistry)