Hi everyone, I'm having problems with effective nuclear charge. Regarding these problems.

Question

Calculate Zeff for a valence electron in an oxygen atom.
and
Calculate Zeff for the 4s electron in a copper atom, .
and
Calculate Zeff for a 3d electron in a copper atom, Cu.

Like for the first question it was Zeff= 8-2
= +6 but it was wrong so i'm lost.

The question gave further info with regards to the formula Zeff= Z-S

where is true nuclear charge and is the amount of shielding.
In 1930, John C. Slater devised the following set of empirical rules to estimate for a designated or electron:

Write the electron configuration of the element, and group the subshells as follows: (1s), (2s, 2p), (3s, 3p), (3d), (4s, 4p), (4d), (4f ), (5s, 5p), and so on.
Electrons in groups to the right of the (, ) group contribute nothing to the shielding constant for the designated electron.
All the other electrons in the (ns,np ) group shield the designated electron to the extent of 0.35 each.
All electrons in the n-1 shell shield to the extent of 0.85 each.
All electrons in the n-2 shell, or lower, shield completely—their contributions to the shielding constant are 1.00 each.
When the designated electron is in an nd or nf group, rules (i), (ii), and (iii) remain the same but rules (iv) and (v) are replaced by the following:
Each electron in a group lying to the left of nf or nd group contributes 1.00 to the shielding constant.
These rules are a simplified generalization based on the average behavior of different types of electrons.

Answer 1

I have several questions?
1. Did you look at the web site I gave you yesterday or the day before? That contained a calculator which I THINK (but not sure) was devised to follow the Slater rules.
2. Since there are a set of rules for each of the three questions you have asked, what problems are you having following those rules? It seems relatively simple to plug in the numbers for the electrons.
3. In the additional information you gave, I am assuming you omitted the Z and the S. Am I correct that it should read as follows:
whereZis true nuclear charge andS is the amount of shielding.