1d) periodic table

• Periodic Table

  Elements are arranged in order of atomic (proton) number, in groups and periods

  
• Elements in the Periodic Table

  • Elements with similar properties are in columns, known as groups
  • Elements with the same number of shells of electrons are arranged in rows called periods

  
• Electronic configuration

  Tells you how many electrons are in each shell around an element's nucleus
• Electrons fill the shells closer to the nucleus before filling any further out
• The 1st shell holds 2 electrons, the 2nd and 3rd shells hold 8 electrons
• Metals

  • Generally conductive (of electricity)
  • If an element is conductive and its oxide is basic, then the element is a metal
• Non-metals

  • (excluding graphite) are not conductive
  • If an element is not conductive and its oxide is acidic, then it's a non-metal
• Metals

  • Elements that react to form positive ions
  • Majority of elements are metals
  • Found to the left and towards the bottom of the periodic table
• Non-metals

  • Elements that do not form positive ions
  • Found towards the right and top of the periodic table
• The divide between metals and non-metals can be seen by the red line in the periodic table at the top
• Group number

  Gives the number of electrons in the outer shell
• Period number

  Gives the number of electron shells
• The number of electrons in the outer shell is responsible for the way different elements react
• Elements in the same group have the same number of electrons in the outer shell and undergo similar reactions
• The noble gases (Group 0) have 8 electrons in their outer shell (except helium, which has 2)
• The noble gases are unreactive and do not easily form molecules, because they have a stable arrangement of electrons