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

Bhor for He atom

  1. Apr 8, 2005 #1
    A singly ionized helium atom (He+) has only one electron in orbit about the nucleus. What is the radius of the ion when it is in Bohr orbit number 3.0?

    I used r=n^2*ao, but this equation looks like its only for hydrogen atoms. I'm just a bit confused because my books seemed to give the same rules for He and Li atoms.
  2. jcsd
  3. Apr 8, 2005 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    a0 is different for the He+-ion (or the Li++-ion) than that for the H-atom. When deriving a0, make the nuclear charge z=2 (instead of z=1). That's the only change you need to make, and you will be good.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook