metals and non metals

• Metals:

  • Metals in their pure state have a shining surface known as metallic lustre
  • Some metals can be beaten into thin sheets, known as malleability
  • Gold and silver are the most malleable metals
  • Metals are generally hard, with varying degrees of hardness
  • Metals can be drawn into thin wires, known as ductility
  • Gold is the most ductile metal
  • Metals are good conductors of heat
  • Silver and copper are the best conductors of heat
  • Metals can conduct electricity
  • Metals that produce a sound on striking a hard surface are sonorous
• Non-metals:

  • Non-metals include carbon, sulphur, iodine, oxygen, and hydrogen
  • Non-metals do not have a shining surface like metals
  • Most non-metals do not conduct electricity
  • Non-metals do not have the properties of malleability and ductility like metals
  • Non-metals can produce acidic oxides when dissolved in water
• Anodising is a process of forming a thick oxide layer of aluminium
• Aluminium develops a thin oxide layer when exposed to air
• The resistance of aluminium to corrosion can be improved by making the oxide layer thicker
• During anodising, a clean aluminium article is made the anode and is electrolysed with dilute sulphuric acid
• The oxygen gas evolved at the anode reacts with aluminium to make a thicker protective oxide layer
• The oxide layer can be dyed easily to give aluminium articles an attractive finish
• Sodium is the most reactive of the samples of metals taken
• Magnesium is less reactive than sodium
• Burning in oxygen does not help to decide about the reactivity of zinc, iron, copper or lead
• Metals react with water to produce a metal oxide and hydrogen gas
• Metal oxides that are soluble in water dissolve to form metal hydroxide
• Potassium and sodium react violently with cold water
• Calcium reacts with water less violently, and the heat evolved is not sufficient for the hydrogen to catch fire
• Magnesium does not react with cold water, but reacts with hot water to form magnesium hydroxide and hydrogen
• Metals like aluminium, iron, and zinc do not react with water, but they react with steam to form metal oxide and hydrogen
• Metals such as lead, copper, silver, and gold do not react with water at all
• Metals react with acids to give a salt and hydrogen gas
• The reactivity decreases in the order Mg > Al > Zn > Fe
• Copper does not react with dilute hydrochloric acid
• Reactive metals can displace less reactive metals from their compounds in solution or molten form
• The reactivity series is a list of metals arranged in the order of their decreasing activities
• The reactivity series includes metals like potassium, sodium, calcium, magnesium, aluminium, zinc, iron, lead, copper, silver, mercury, and gold
• Ionic compounds are formed by the transfer of electrons from a metal to a non-metal
• Cation: Mg 2+ (Magnesium cation)
• Anion: Cl - (Chloride anion)
• Properties of ionic compounds:
• Physical nature: Ionic compounds are solids and somewhat hard due to strong force of attraction between positive and negative ions
• Melting and Boiling points: Ionic compounds have high melting and boiling points
• Solubility: Ionic compounds are generally soluble in water and insoluble in solvents like kerosene and petrol
• Conduction of Electricity: Ionic compounds conduct electricity in molten state but not in solid state
• General properties of ionic compounds:
• Physical nature: Ionic compounds are solids and brittle, breaking into pieces under pressure
• Metals such as copper, zinc, tin, nickel, silver, gold, etc., are refined electrolytically
• In this process, the impure metal is made the anode and a thin strip of pure metal is made the cathode
• A solution of the metal salt is used as an electrolyte
• Pure metal from the anode dissolves into the electrolyte, while an equivalent amount of pure metal from the electrolyte is deposited on the cathode
• Soluble impurities go into the solution, while insoluble impurities settle down at the bottom of the anode as anode mud
• Pure gold, known as 24 carat gold, is very soft and alloyed with silver or copper to make it hard