Effective Nuclear Charge

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Natalie Yakobian
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Effective Nuclear Charge

Postby Natalie Yakobian » Thu Oct 08, 2015 1:13 pm

Hi I'm a little unclear on what Zeff is. Can someone please explain it to me?

Last edited by Natalie Yakobian on Fri Oct 09, 2015 5:26 pm, edited 1 time in total.

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Joined: Fri Sep 25, 2015 3:00 am

Re: Effective Nuclear Charge

Postby kshalbi » Thu Oct 08, 2015 5:35 pm

Zeff, effective nuclear charge, is the positive charge experienced by an electron. Z, is the charge of the nucleus, which is positive. Imagine a valence electron in the outermost orbital. It is repelled from the nucleus by all the negatively charged electrons that surround the nucleus. Thus, these electrons are shielding the valence electron and in turn it can't experience the full charge from the nucleus. Effective nuclear charge increases as you go from left to right of the periodic table. This makes sense because as you go from left to right on the table, one proton is being added to the nucleus of the atom. You are also adding one electron, but the electron's ability to shield other electrons will not be as strong as the proton's ability to attract electrons.
Zeff= Z(nuclear charge) - S(shielding constant)

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