1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Ground state of Potassium and Hydrogen

  1. Apr 13, 2012 #1
    1. The problem statement, all variables and given/known data

    For potassium in ground state configuration (Z=19) how would you expect the energy of the least tightly bound electron to compare with the energy of the electron in hydrogen excited to a state of the same principal quantum number n. Explain your answer.

    2. Relevant equations

    None

    3. The attempt at a solution

    Ok, so in it's ground state in standard notation Potassium 19 is:

    K 1s[itex]^{2}[/itex] 2s[itex]^{2}[/itex] 2p[itex]^{6}[/itex] 3s[itex]^{2}[/itex] 3p[itex]^{6}[/itex] 4s[itex]^{1}[/itex]

    I'm guessing that the principal quantum number that it's asking for is when n=4 in the hydrogen? If so where do I go from here?

    Any help is gratefully received
     
  2. jcsd
  3. Apr 13, 2012 #2
    Is it perhaps that when the quantum number n=4 in the hydrogen atom the eV value ≈ -0.85eV (-13.6ev/4^2)? Because the angular momentum quantum number l = 0 then it has less energy and is closer to the nucleus?

    I'm kinda clutching at straws
     
  4. Aug 9, 2012 #3
    1s 2 2s 2 2p 6 3s 2 3p 6 electron will screen the nucleus of K, it seems that the 4s electron is attracted by 1 charge(19-18),but it doesn't screen so good,so the 4s electron will see more than 1 charge,for example 2,this situation will increase the attraction force to the 4s electron resulting in the decreasing of the energy.In contrast to hydrogen atom ,the nucleus is just 1 charge.so the energy of 4s electron will lower than that of the 4s electron of hydrogen.
     
  5. Aug 9, 2012 #4
    Last edited: Aug 9, 2012
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook