Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Fajans rule?

  1. Dec 30, 2007 #1
    fajans rule??

    hey can anyone help me with fajans rule?

    after the emission of alpha rays from a radioactive substance the product remaining has a valency of 2. after the emission of beta rays it has a valency increase of 1. so the ionic depletion changes the valency.

    thus meaning reducing the ions changes the valency

    is this right???
    Last edited: Dec 30, 2007
  2. jcsd
  3. Dec 30, 2007 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    What does this have to do with Fajan's rules?

    In any case, the important thing to keep in mind is that it is harder to change the nuclear composition (number of protons and neutrons) than the electronic composition. Once the number of protons is changed, the resulting ion will attract or throw away the necessary number of electrons to stay neutral. So, if the atom gains/loses n protons through radioactive decay, it will then pick up/throw out n electrons as well.

    With this in mind, make sure you can follow what is happening with the atom above. What would have been the valency before alpha emission? Do the subsequent changes in valency make sense?
  4. Dec 30, 2007 #3
    thats what my tutor taught me and i was confused about it. thanks for the help =]
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook