level: Group7
Questions and Answers List
level questions: Group7
| Question | Answer |
|---|---|
| Halogens are joint by what force | London |
| Trends in boiling points group 7 | decreases down a group more electrons, stronger london forces, more energy required to break the imf ,boiling point increases |
| all group 7 | gain an electron so reduced |
| displacement reactions colours | hallides in water = colourless cl2= pale green br2= orange I2= brown (water) = violet (cyclohexane) |
| Ionic equation displacement for chlorine and iodine | Cl2 + 2I- ---> 2cl- + I2 so colour goes from pale green to brown |
| Trend in reactivity group 7 | - Atomic radius increases - Shielding increases -Less nuclear so reactivity decreases harder to gain an electron |
| Disproportionation | the same element is both oxidised and reduced at the same time eg Cl2 + H20 ---> HCl0 + HCL |
| Benefits and risks of chlorine | Kills bacteria in water (B) causing cancer (R) |
| Testing for halogens | add silver nitrate cl- white br- cream iodine - yellow |