halogens

• explain the pattern of melting points down the group?

  melting points increase down the group because there are more electrons in the elements so more van der waal intermolecular forces which takes more energy to overcome.
• fluorine

  • F2
  • highly reactive
  • highly poisonous
• what is the appearance of fluorine?

  pale yellow gas
• Chlorine

  • Cl2
  • highly poisonous
  • dense
• what's the appearance of chlorine?

  pale green gas
• Bromine

  • Br2
  • highly poisonous
  • toxic
  • dense
• Iodine

  • I2
  • produces a purple gas
  • poisonous
• what is the appearance of bromine?

  red brown liquid that gives off fumes readily
• whats the appearance of iodine?

  dark grey crystalline solid
• what is the reactivity trend for group 7 ?

  decreases as you go down the group
• how do group 7 atoms react?

  gain an electron to achieve a full outer shell
• explain the reactivity trend of the halogens?

  • decreases as you go down the group
  • atomic radius increases
  • less attraction to the nucleus
  • more shielding
  • stronger electrostatic attraction
• what do all halogens have in common?

  7 electrons in the outer shell
• what is the electronegativity trend going down group 7 ?

  • decreases down the group
  • atomic radius increases
  • shielding increases
  • attraction between nucleus and bonding pair of electrons decrease
• Why does iodine have a higher melting point than bromine?

  • more electrons
  • more van der waal intermolecular forces
  • more heat energy to overcome
• why is fluorine more reactive than iodine?

  • fluorine has a smaller atomic radius than iodine
  • stronger electrostatic attraction between the nucleus and the outer electrons which takes
• why can the halogens act as oxidising agents?

  able to readily gain an electron
• explain the trend in oxidising ability

  • decreases as the atomic radius and shielding increases
  • the electron gain is less attracted to the nucleus
• Explain the trend in reducing ability

  • increases as the atomic radius and shielding increases
  • the outer electrons have a weaker attraction to the nucleus so takes less energy to be loss
  • better able to donate electrons
• what are the observations between sodium chloride and sulphuric acid?

  • fizzing
  • white misty fumes
  • turned damp litmus paper red (acidic)
  • white solid remaining- some NaHSO4 formed
• what are the observations between sodium bromide and sulphuric acid?

  • fizzing white misty fumes
  • turned damp litmus paper red (acidic)
  • white solid remaining- some NaSO4 formed
  • colourless gas formed from H2SO4 + SO2 ( choking gas)
• what are the observations between sodium iodide and sulphuric acid (rotten egg gas)?

  • fizzing
  • white misty fumes
  • turned damp litmus paper red (acidic)
  • white solid remaining - some NaHSO4 formed
  • brown/ black solid remains (iodine)