Chapter 4 - Periodic Table

• Group 1

  • Alkali metal
  • Physical properties: The lower the group, m.p & b.p. decrease ; softness and density increase
  • Chemical properties: The lower the group, reactivity increase because the distance of valance electron from nucleus
• Group 7

  • Poisonous
  • Diatomic
  • Halogens
• Reaction of metal with water

  1. Metal + water → Lithium hydroxide

  2. 2Li + 2H2O → 2LiOH
• Fluorine

  • Pale yellow
  • Gas
• Chlorine

  • Green
  • Gas
• Bromine

  • Reddish brown
  • Liquid
• Iodine

  • Greyish black
  • Solid
• Astatine

  • Black
  • Solid
• Group 7

  • Physical Properties: the lower the group, m.p & b.p increases ; darkness of colour and density increases
  • Chemical Properties: the lower the group reactivity decrease
• Halogen + Group 1 metal

  Metal nalide
• Example of Halogen + Group 1 metal

  • Chlorine + Sodium → Sodium chloride
  • Cl2 + 2Na → 2NaCl
• Displacement reaction

  More reactive element will displace a less reactive element in salt solution/compound
• Group 8

  • Noble Gas
  • Non-metal
  • Colourless at room temp
  • Unreactive (Inert) (Stable electronic configuration)
  • Monatomic (cannot form bond)
  • Physical Properties: the lower the group, density and m.p & b.p increases
• Helium (He)


  • Applications: Air balloon, Diver's tank
• Transition elements


  Properties:

  • Conduct heat
  • Conduct electricity
  • Malleable
  • Ductile
  • Shiny
  • Sonorous
• Transition elements

  • Physical properties:
  • Stronger & harder than Group 1,2,3,
  • Higher melting and boiling points than Group 1,2,3
  • Higher density than Group 1,2,3
• Transition elements

  • Chemical properties:
  • Lower reactivity than Group 1,2,3
  • Form coloured compounds (Cu, Fe)
  • Have multiple oxidation states
  • Form complex ions
  • Good catalysts (matchmaker)
• Catalyst:

  • A substance that accelerates a chemical reaction but remains unchanged itself (no reaction with others)
  • Only require little amount
  • Specific
• Neon (Ne)

  • Application: Advertisement light
• Argon (Ar)

  • Application: lightbulb (fluoroscent)
• Krypton (Kr)

  • Application: airplane running lights
• Xenon (Xe)

  • Application: camera flash light
• Radon (Rn)

  • Application: treat cancer
• Periodic Table

  • the upper the group
  • increased electromagnetic (tendency to attract electron)
  • Ionisation energy increase (energy to extract electron for atom)
• Periodic Table

  • the lower the group
  • atomic size increase (more electron shells)
  • metallic properties increase (more shells, valence electron further from nucleus, experience lesser attractive force, lose its outer shell electron more easily)
• Group 1,2,3

  • positive ions
  • metal
  • lose electron to form positive ions
  • charge is same as group number of element forming it
• Group 4,5

  • tend to form covalent instead of ionic compound
  • share electrons to form covalent bond
  • have maximum oxidation number that is same as group number of element
• Group 6,7

  • negative ions
  • non-metals
  • tend to gain electrons to form negative ions
• Group 8

  • do not form compounds
  • have stable electronic configurations