reactions of metals

• Non-metals


  • Can be shiny and reflect light, but do not conduct electricity
  • Graphite conducts electricity well, but is brittle and breaks easily
  • Many plastics can be drawn out into threads and can change shape without breaking, but they do not conduct electricity
• Metals


  • Have high melting points and can reflect light, conduct electricity, have their shape changed, and be drawn out into wires without breaking
• Since the Bronze Age, about 4000 years ago, people have been extracting metals from the earth
• They have melted these metals to make tools and weapons
• Alloy


  A mixture of metals or a mixture of metal and any other element
• Malleable


  Able to be hammered into thin sheets without breaking
• Ductile


  Able to be drawn into a wire without breaking
• Metals are dense, most are much denser than non-metals
• The high density is due to the closely packed atoms
• Metals


  • Atoms are packed closely together
  • Outermost electrons are not tied to any atom and are free to move
• Conductor


  Allows electric current to flow because the free electrons can move
• Insulator


  Does not have a 'sea' of free electrons, so does not conduct electricity
• Metal reacting with water

  1. Sodium and potassium react violently, giving off hydrogen gas and forming alkalis

  2. Magnesium reacts very slowly with cold water but reacts violently with steam

  3. Unreactive metals like gold do not react with water
• Metal reacting with acids

  1. Unreactive metals do not react

  2. Some metals like magnesium react, producing hydrogen gas

  3. Reactive metals like calcium, sodium, and potassium react violently
• Metal reacting with air/oxygen

  1. Reactive metals like magnesium burn easily in oxygen, producing oxides

  2. Calcium, sodium, and potassium also react quickly in air

  3. Unreactive metals like gold and silver do not react and stay shiny
• Reactivity series


  Metals arranged in a 'league table' according to how they react
• Potassium is at the top of the reactivity series, gold and platinum are at the bottom
• Metals higher in the reactivity series can displace metals lower in the series from their compounds
• Only metals at the bottom of the reactivity series, like gold and silver, can be found in rocks as the pure metal
• Other metals are found in rocks as compounds called ores
• Ore


  A compound of a metal found in rocks, from which the metal can be extracted
• Extracting metals from ores is quite difficult, normally done in two stages: separating the metal compound from the rock, then extracting the metal
• Extracting aluminium


  Aluminium ore (bauxite) is purified to aluminium oxide, then electrolysis is used to extract pure aluminium
• Extracting iron


  Iron oxide is separated from impurities, then heated with carbon in a blast furnace to remove oxygen and produce pure iron
• Corrosion


  A chemical attack on the surface of a metal, causing it to lose its shiny appearance and be slowly eaten away
• Corrosion is a major problem for metals, weakening and damaging objects made from them
• Preventing corrosion


  1. Coating with paint, grease, or electroplating to prevent air reaching the metal

  2. Using sacrificial anodes of more reactive metals to protect less reactive metals
• Alloy


  A mixture of two or more metals, designed to be resistant to corrosion
• Steel is a commonly used alloy, with iron as the main metal, alloyed with other metals like nickel and chromium to make it stronger and more rust-resistant
• Magnesium reacts vigorously with oxygen to form magnesium oxide (MgO).
• Metals reacting with water


  Metal + water-> Hydrogen gas + Metal hydroxide
• Metals reacting with water

  • Sodium+ water → Hydrogen gas + Sodium hydroxide
• Metals reacting with acid


  Metal & acid =Salt + Hydrogen gas
• Metals reacting with acid

  • Sodium + acid =salt (Sodium chloride) + Hydrogen gas
  • Magnesium + acid =Salt (magnesium chloride) + Hydrogen gas
• Metals reacting with oxygen or air


  metal + oxygen → metal oxide
• Metals reacting with oxygen or air


  • Iron + oxygen=Iron oxide (Rust)
• Displacement reactions


  Magnesium +oxygen (steam) =magnesium + hydrogen
• Magnesium is more reactive than copper


  When a piece of magnesium is dipped into blue copper sulphate solution, a displacement reaction occurs. The magnesium displaces copper, and the products are copper and a solution of magnesium sulphate.
• Displacement reactions


  • Magnesium + copper sulphate= magnesium sulphate