TRENDS

• ELEMENTS AND THEIR TRENDS IN PERIOD 3?

  Na, Mg, Al

  • metallic
  • shiny
  • conduct electricity
  • react with dilute acid to produce salts and hydrogen

  Si

  • metalloid
  • conducts electricity to an extent

  P, S, Cl

  • non-metals
  • do not conduct electricity
  • low melting/ boiling points

  Ar

  • noble gas
  • inert
• TREND IN MELTING POINTS OF PERIOD 3 ELEMENTS?

  Na, Mg, Al

  • metallic bonding
  • more delocalised electrons
  • smaller atomic radius
  • greater electrostatic attraction between positive ions and delocalised electrons
  • stronger metallic bond

  Si

  • giant covalent molecule
  • strong covalent bonds

  P4, S8, Cl2

  • simple molecular compounds
  • van der Waals
  • weak intermolecular forces
  • larger molecule more electrons
  • greater number of electron clouds
  • stronger induced dipole-dipole forces
  • stronger van der Waals

  Ar

  • noble gas
  • monoatomic element
  • very weak van der Waals