Periodic table

• How did scientist used to group elements

  By their atomic weight
• What did Mendeleev do

  Grouped elements based on properties
• why did Mendeleev leave gaps

  Elements were yet to be discovered
• What order do electron shells fill

  2,8,8,2
• Where are metals on the table

  Left side
• Where are non-metals on the table 


  Right
• What do metals do

  • Donate electrons to gain empty outer shell
  • Form positive ions
• What do non-metals do

  Gain electrons to have a full outer shell

  • Form negative ions
• What does the group number tell us

  Number of electrons in outer shell
• What are group 1 metals called

  Alkali

  • Lose their outer electron - ions are all positive
• What happens when you go down group 1

  Get more reactive

  • As outer shell is further from nucleus
• What is group 7 called

  Halogens

  • Form negative ions - gain 1 electron to get full outer shell
• What happens when you go down group 7

  Get less reactive

  • Boiling point increases
• What is group 0 called

  Noble gases

  • Very unreactive
  • Already have empty outer shell
• What is the order of electronic configuration

  2,8,8,2