Revision-Chemistry

• Group 0 elements are called noble gases.
• group 0 elements are all inhert colourless gases.
• Transition Metals


  • Can have more than one ion
  • Ions are often colored
  • Compounds containing them are often colorful
  • Can act as good catalysts
• Solids

  • have a fixed shape and cannot flow , because their particles cannot move from place to place.
  • cannot be compressed because their particles are closely packed together and have no space to move into.
• Liquid

  • flow and take shape of their container, because their particles are able to move around each other.
  • can be compressed.
• Gas

  • flow and completely fill the container ,because their particles can move quickly in all directions.
  • can be compressed, their particles are far apart and have space to move into.
• Ions

  An ion is an group of atoms with a positive or negative charge.
• Positive ions

  Metal atoms lose electrons from there outer shell and become positively charged.
• Negative ions

  The outer shells of non-metals gains electrons and therefore becomes negative.
• The ionic lattice

  An ionic compound is a giant structure of ions. They have a regular , repeating arrangement called an ionic lattice.
• Positive+ & Negative- =attract
• Ionic compounds

  Ionic compounds have a high boiling and melting point , so they are in solid state at room temperature.
• Compounds

  Compound are formed when 2 or more elements are chemically bonded together by sharing or giving electrons.
• Protons ,Neutrons & Electrons

  • protons- positively charged ,same mass as neutron (1).
  • electrons-negative , mass nearly nothing.
  • neutrons-neutral , mass same as proton(1).
• Relative mass & charge

  proton: relative mass- 1, relative charge =+1.

  neutron: relative mass - 1, relative charge=0

  electron: relative mass- 0, relative charge -1
• Isotope- an isotope is an atom with a different number of neutrons.
• Covalent bonding- when 2 or more non- metals share an electron(S).
• Metalic bonding- the bonding of metals in a lattice surrounded by delocalised electrons.
• Alloy- mixture of metals
• Mr=molecular

  Ar=atomic