C2 - periodic table

• what do all elements in a group share

  Similar chemical properties - same number of electrons in outer shell
• what is döbereiners triad

  elements with similar chemical properties often occur in triads
• examples of döbereiners triad

  lithium, sodium and potassium all react rapidly with water

  chlorine bromine and iodine are all reactive non metals
• what is newlands octaves

  • ordering elements in atomic weight
  • every eighth element reacts similarly
• how did mendeleev form the modern periodic table 


  1. ordered all elements in increasing atomic weight
  2. he would switch order of specific elements when needed to fit the patterns of other elements in the same group
  3. left gaps in the table for elements that were yet to be discovered
• what is group 0

  noble gases
• Why are noble gasses extremely unreactive

  They are stable with a full outer shell
• what outer shell do noble gases have

  full unreactive outer shells
• boiling points of noble gases

  • lower than room temperature
  • increases as relative atomic masses increases (move down)
• Where are metals and non metals

  Non metals - right

  Metals– left
• how are metal categories divided

  highly reactive - group 1 and 2

  transition metals (less reactive)
• key points about metals

  • when metals react they lose electrons to achieve a full outer shell
  • gives them stable electronic structure of noble gas
  • always form positive ions
• if you remove an electron what is the charge

  positive - forms an ion - draw a square bracket with overal charge
• What are group 1 metals

  alkali
• lithium reacting with oxygen

  • soft metals
  • reacts rapidly with oxygen
  • forms compound lithium oxide
• how does the reaction with oxygen change down group 1

  react more rapidly
• reaction of alkali with water

  • reacts rapidly
  • effervescence/fizzing shows a gas is produced
  • universal indicator turns from green to purple showing an alkaline solution
  • react more rapidly as move down group
• equation for lithium and water

  lithium + water - lithium hydroxide (alkaline) +hydrogen (gas)
• Why is the reaction with oxygen more rapid down group 1

  -Looses outer shell easier

  - radius of atoms increases giving greater distance between positive nucleus and negative electron - less attracted the further away

  -outer electron is repelled by electrons in internal energy levels (shielding) decreasing attraction between nucleus and outer electron
• what is group 7

  halogens - non metals
• how many electrons do group 7 elements have

  7
• how do halogens react together

  forming molecules of two atoms joined by a covenant bond
• How do the melting and boiing points of group 7 show their state at room temp

  • melting and boiling points increase increases down group 7
  • Boiling point less than 20 is a gas at room temp
  • Melting point less than 20 but boiling point higher than 20is a liquid at room temp
  • Both melting and boiling point higher than 20 is solid at room temp
• what happens to relative molecular mass down group 7

  increases - molecules get bigger down group 7
• What do group 7 elements form when reacting with other non metal elements

  covelant compounds
• what happens when halogens react with metals

  form ionic compounds
• how does reactivity change down group 7

  decreases
• why does reactivity decrease down group 7

  • lower elements gain electrons less easy
  • greater distance between outer energy level and nucleus - less attracted to nucleus
  • more electrons in internal energy levels - repel outer electrons (sheilding)
• displacement of halogens

  • a more reactive halogen can displace a less reactive halogen from an aqueous solution of its salt
  • sodium bromide + fluorine - sodium fluoride + bromine