metals

• Metals lie to the left of the zig-zag line in the Periodic Table
• Over 80% of the elements are metals
• Physical properties of metals:

  • Strong and hard to break
  • Malleable and can be hammered into shape
  • Ductile and can be drawn out into wires
  • Sonorous and make a ringing noise when struck
  • Shiny when polished
  • Good conductors of electricity and heat
  • Have high melting and boiling points
  • Have high density
• Chemical properties of metals:

  • React with oxygen to form oxides
  • Metal oxides are bases
  • Metals form positive ions when they react
  • Transition elements have variable valency
  • Charge on the ion is the same as the group number for numbered groups
• Not all metals share typical metal properties

  • Iron is malleable, strong, rusts easily, and is magnetic
  • Sodium is soft, reacts with water, and melts at a low temperature
  • Gold is unreactive, malleable, ductile, and rare
• Reactivity of metals:

  • Reactive elements have a strong drive to become compounds
  • Reactive metals react readily with other elements and compounds
  • Metals can be put in order of reactivity based on their reactions with water and hydrochloric acid
• Competition of metals:

  • Magnesium is more reactive than carbon
  • Carbon is more reactive than lead
  • Iron, zinc, and lead are more reactive than copper
  • Metals compete to form compounds with carbon and oxygen
• Reactivity series:

  • Lists metals in order of reactivity
  • More reactive metals displace less reactive metals from compounds
  • The series helps predict reactions and extraction methods
• Metals of the reactivity series, in order:

  • Potassium
  • Sodium
  • Calcium
  • Magnesium
  • Aluminium
  • Zinc
  • Iron
  • Lead
  • Copper
  • Silver
  • Gold
• Potassium, Sodium, Calcium, Magnesium, Aluminium, Zinc, Iron, Lead, Copper, Silver, and Gold are found in the Periodic Table
• The most reactive metals belong to Group 1 in the Periodic Table
• The least reactive metals are found in the last group of the Periodic Table
• Magnesium is never found as the element in nature because it is highly reactive and readily forms compounds
• Gold has been known and used for thousands of years longer than aluminium because gold is unreactive and occurs native in the Earth's crust
• Magnesium nitrate will break down more easily on heating compared to silver nitrate because magnesium is more reactive
• Balanced equation for the thermal decomposition of lead(II) nitrate:

  Pb(NO3)2(s) → PbO(s) + NO2(g) + O2(g)
• The lower a metal is in the reactivity series, the more readily its compounds decompose when heated
• Carbonates, except those of sodium and potassium, decompose to the oxide and carbon dioxide
• Hydroxides, except those of sodium and potassium, decompose to the oxide and water
• Nitrates, except those of sodium and potassium, decompose to the oxide, nitrogen dioxide, and oxygen. The nitrates of sodium and potassium form nitrites and oxygen
• The most reactive metals are not quite plentiful in the Earth's crust
• Some metals are called precious because they are rare and valuable
• Four precious metals are silver, gold, platinum, and palladium
• One metal used more than all others put together is aluminum because it is abundant and has various uses
• A metal ore is a rock that contains enough of a metal or its compound that it can be extracted economically
• Main ore of sodium is rock salt (halite) and the main compound is sodium chloride (NaCl)
• Main ore of aluminum is bauxite and the main compound is aluminum oxide (Al2O3)
• Extraction of metals from their ores depends on the metal's reactivity
• The most unreactive metals like silver and gold occur in their ores as elements and do not require chemical reactions for extraction
• The compounds of more reactive metals need electrolysis for reduction, which is costly due to electricity usage
• Carbon can be used as a reducing agent for metals less reactive than itself
• In the extraction of lead, lead oxide is reduced to lead by carbon, where carbon is the reducing agent
• The reaction in question 2 is a redox reaction because there is both reduction and oxidation occurring
• Sodium is extracted from rock salt through electrolysis because it is highly reactive and cannot be reduced by carbon
• Balanced equation for the extraction of sodium from rock salt: 2NaCl (l) -> 2Na (l) + Cl2 (g)
• Zinc blende is mainly zinc sulfide (ZnS)
• Extraction of zinc by electrolysis involves dissolving zinc oxide in sulfuric acid, then undergoing electrolysis to deposit zinc at the cathode
• Iron ore is mainly iron(III) oxide (Fe2O3) and is reduced using carbon monoxide
• Blast furnace is used for extracting iron from its ore, hematite, which contains iron(III) oxide mixed with sand and other compounds
• The charge in the blast furnace includes iron ore, limestone (calcium carbonate), and coke (pure carbon)