Properties of Metals

• The Periodic Table contains over 100 different elements

  • They can be divided into two broad types: metals and non-metals
• Most of the elements are metals and a small number of elements display properties of both types

  • These elements are called metalloids or semimetals
• The metallic character diminishes moving left to right across the Periodic Table

  
• Properties of metals

  • Conduct heat and electricity
  • Are malleable (can be hammered and made into different shapes) and ductile (can be drawn into wires)
  • Tend to be lustrous (shiny)
  • Have high density and usually have high melting points
  • Form positive ions through electron loss
  • Form basic oxides
• Properties of non-metal elements

  • Do not conduct heat and electricity
  • Are brittle when solid and easily break up
  • Tend to be dull and nonreflective
  • Have low density and low melting points (many are gases at room temperature)
  • Form negative ions through electron gain (except for hydrogen)
  • Form acidic oxides
• The chemistry of metals is studied by analysing their reactions with water, dilute acid and oxygen

  • Based on these reactions, a reactivity series of metals can be produced
• Reactivity with water

  • Some metals react with water, either warm or cold, or with steam
  • Metals that react with cold water form a metal hydroxide and hydrogen gas
  • metal + water →  metal hydroxide + hydrogen
  • For example calcium: Ca (s) + 2H2O (l) → Ca(OH)2 (aq) + H2 (g)
  • Metals that react with steam form metal oxide and hydrogen gas, for example zinc: Zn (s) + H2O (g)  →  ZnO (s) + H2 (g)
• Reactivity with acids

  • Most metals react with dilute acids such as HCl
  • When acids and metals react, the hydrogen atom in the acid is replaced by the metal atom to produce a salt and hydrogen gas, for example iron:
  • metal + acid → salt + hydrogen
  • Fe (s) + 2HCl (aq) → FeCl2 (aq) + H2 (g)
• Reactivity with oxygen

  • Unreactive metals such as gold and platinum do not react with oxygen
  • Some reactive metals such as the alkali metals react easily with oxygen
  • Copper and iron can also react with oxygen although much more slowly
  • When metals react with oxygen a metal oxide is formed, for example copper: metal + oxygen → metal oxide
  • 2Cu (s) + O2 (g) → 2CuO (s)
• Structure of metal

  • attraction between metal ions and electrons cause a metallic bond

  
• Physical properties of metals

  • conduct electricity and heat
  • high melting/boiling points - only transistion metals
  • ductile - drawn into a wire (only some aka transition metals)
  • malleable - bent into shape using a hammer
  • lustre - shiny
  • high density - only transition metals
• Properties of non-metals

  • dull
  • low melting points - only simple molecular compounds e.g. CO2 as giant covalent compounds have high melting and boiling points
  • poor conductors - except for graphite
  • low density
  • brittle
• High melting and boiling points explanation - strong attraction between nucleus of positive ions and delocalised electrons
• Conducts electricity and heat explanation - outershell electrons free to move and carry charge through metal or heat
• Strong strength but soft explanation - layers can slide while maintaining metallic bonding
• Malleable and ductile explanation - structure maintained when drawn into wires or hammered into shape