group 7

• what is another word for group 7 metals?

  halogens
• what are the halogens?

  non-metals that are poisonous
• how many electrons do they have in the outermost shell?

  7
• the halogens are ____A____, meaning they form molecules made of ____B__ of atoms, sharing _____C_____ (forming a single ___D__ bond between the 2 halogen atoms)

  a - diatomic

  b - pairs

  c - electrons

  d - covalent
• what happens to the melting/boiling points of the halogens as you go down the group?

  they increase.

  • the atoms get bigger down the group
  • the intermolecular forces increase
  • so more energy is required to overcome these forces
• at room temperature, the physical state of the halogens also changes as you go down the group. do you agree with this statement?

  yes i agree because fluorine and chlorine are gases, bromine is a liquid and iodine is a crumbly solid
• what happens to the colours of the halogens as you descend the group?

  they get darker
• what happens to the reactivity of the halogens as you descend the group?

  it decreases.

  • shells of electrons increase - atom size increases
  • forces of attraction between the nucleus and the outermost shell decrease
  • this makes it harder for atoms to gain electrons
• when does a halogen displacement reaction occur?

  when a more reactive halogen displaces a less reactive halogen from an aqueous solution of its halide.
• which is the most reactive out of these 3: chlorine, bromine and iodine

  chlorine
• which is the least reactive out of these 3: chlorine, bromine and iodine

  iodine
• chlorine + potassium bromide --> potassium ___A_____ + ____B___

  a - chloride

  b - bromine
• what colour does the solution turn if bromine is formed?

  orange
• what colour does the solution turn if iodine is formed?

  brown
• is bromine more reactive than iodine?

  yes
• what is made when bromine reacts with potassium iodide?

  potassium bromide and iodine