Wednesday, 1 May 2013

2.13 describe the relative reactivities of the elements in Group 7

Group 7 elements become less reactive as you go down the group.

At the top, the positive charge of the proton in the nucleus is close to the surface (as there are few shells) this makes it easy for them to pull in the one electron they need to become stable, meaning they are very reactive.

Lower down where there are more shells the pull of the proton is further from the surface making it less easy to pull in another electron.


  1. this really contradicts Group 1 metals.

    1. It is a bit confusing but remember group 7 is trying to do the opposite of group 1. The attraction to potential new electrons is stronger if the atom is smaller as it's closer to the positively charged nucleus. Hope this helps :)

  2. This is from the CGP book and is a bit less confusing:

    The higher up Group 7 an element is, the more reactive it is. This is because the shell with the missing electron is nearer to the nucleus, so the pull from the positive nucleus is greater.

    Hope this helps.