Group 7

• What type of elements are group 7 elements?

  Highly reactive non-metals
• Why do group 7 elements form a 1- ion?

  To achieve a full outer shell of electrons
• How does the atomic radius of group 7 elements change down the group?

  It increases down the group
• What causes the atomic radius to increase down group 7?

  Additional electron shells
• How does reactivity change down group 7 elements?

  Reactivity decreases down the group
• Why does reactivity decrease down group 7 elements?

  Increased atomic radius weakens nucleus attraction
• What happens to the first ionisation energy of group 7 elements down the group?

  It decreases down the group
• What is the reason for the decrease in first ionisation energy down group 7?

  Greater atomic radius and increased shielding
• What type of molecules are group 7 elements?

  Simple covalent molecules
• What are negative ions of halogens called?

  Halide ions
• How do halide ions act as reducing agents?

  They donate electrons to other species
• How does reducing power change down group 7?

  It increases down the group
• What is the relationship between reducing power and atomic size?

  Larger ions lose electrons more easily
• What redox reactions with H2SO4 should be known?

  1. Fluoride and Chloride ions
  2. Bromide ions
  3. Iodide ions
• What is used to test for halide ions?

  Acidified silver nitrate
• What do different halide ions form with silver nitrate?

  Different coloured precipitates
• How do van der Waals forces change down group 7?

  They increase down the group
• What is the boiling point trend for group 7 elements?

  Boiling point increases down the group
• What state is fluorine at room temperature?

  Gas
• What state is iodine at room temperature?

  Solid
• How do halogens act as oxidising agents?

  They accept electrons from other species
• How does oxidising power change down group 7?

  It decreases down the group
• What does the relative oxidising strength of halogens indicate?

  A halogen will displace any halide beneath it

  
• What is the trend in atomic radius down Group 7?

  Atomic radius increases down the group
• Why does atomic radius increase down Group 7?

  Due to more electron shells
• What is the trend in electronegativity down Group 7?

  Electronegativity decreases down the group
• Why does electronegativity decrease down Group 7?

  More shielding and greater atomic radius
• What is the physical state and color of fluorine at room temperature?

  Pale yellow gas
• What is the physical state and color of chlorine at room temperature?

  Green gas
• What is the physical state and color of bromine at room temperature?

  Red-brown liquid
• What is the physical state and color of iodine at room temperature?

  Grey solid
• What is the trend in boiling and melting points down Group 7?

  Increases down the group
• Why do boiling and melting points increase down Group 7?

  Due to stronger van der Waals forces
• What is the trend in oxidising ability down Group 7?

  Decreases down the group
• Why does oxidising ability decrease down Group 7?

  Harder to gain electrons
• Which halogen is the strongest oxidising agent?

  Fluorine
• What happens when chlorine is added to potassium bromide?

  Chlorine displaces bromine
• What is the equation for the reaction of chlorine with potassium bromide?

  Cl2 + 2KBr -> 2KCl + Br2
• What is the trend in reducing ability of halide ions?

  Increases down the group
• Why does reducing ability increase down the group?

  Larger ions lose electrons more easily