Question

Which of the following has the largest effective nuclear charge experienced by the valence electrons? *
A.O
B.C
C.Sn
D.Rb

Answer 1

Is this B?

Answer 2

Are you supposed to do this as an estimate or are you to use Slater's Rule.
Zeff = Z - S where Z is the nuclear charge (the number of protons) and S is the shielding of the valence electrons from the nucleus. For the estimated number S is simply the number of inner electrons not in the valence shell and that's pretty easy to do. For a more accurate numbef for Zeff you can look up Slater's rule. There is a set protocol for doing this AND there is a formula for calculating based upon numbers supplied by Slater. For example an s electron use 0.5 but for a p electrons it's a different value. At any rate follow what you've been taught in your class. If you have trouble find info on Slater's Rule let me know and I'll look too.

Answer 3

I'm thinking that probably is the simpler approach so I'll show those below.
Zeffective = Z - S where Z is the nuclear charge;i.e., the number of protons and S is the shielding; i.e., all of the electrons EXCEPT the outside one(s). So for 8O16, that is 1s2 2s2 2p4
Zeff = 8 - 2 = 6
6C is 1s2 2s2 2p2 so Zeff = 6 - 2 = 4
50Sn is [Kr] 4d10 5s2 5p2 Zeff = 50-(36+10) = 4
37Rb is [Kr] 5s1 Zeff = 37-36 = 1