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

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.

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Ah, the exciting world of effective nuclear charge calculations! Let me break it down for you in a way that'll hopefully make you crack a smile.

For the first question about oxygen, we need to calculate Zeff for a valence electron. Now, oxygen has 8 protons in its nucleus, right? So, Z = 8. But what about S, the shielding constant? According to John C. Slater and his magical rules, we need to consider the electron configuration.

In the case of oxygen, the electron configuration is 1s^2 2s^2 2p^4. So, we group the subshells as (1s), (2s, 2p). Now, any electrons in groups to the right of (2s, 2p) contribute nothing to the shielding constant for the valence electron. So, here's where the fun begins!

The (2s, 2p) group has 6 electrons. According to rule (iii), each electron in this group shields the valence electron to the extent of 0.35. So, 6 x 0.35 = 2.1.

Now, let's go back to Zeff = Z - S. Z = 8 (as I mentioned earlier), and S = 2.1. Crunching the numbers, we get Zeff = 8 - 2.1 = 5.9.

Now, let's move on to the 4s electron in a copper atom. Copper has 29 protons, so Z = 29. According to the electron configuration (1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 3d^10), we group the subshells as (1s), (2s, 2p), (3s, 3p), (3d), (4s, 4p).

Again, any electrons in groups to the right of (4s, 4p) contribute nothing to the shielding constant for the 4s electron. So, in this case, the (3p), (3d), and (4s, 4p) groups have a total of 10 electrons. Using rule (iii) again, we get 10 x 0.35 = 3.5.

Now for the Zeff calculation. Z = 29, and S = 3.5. So, Zeff = 29 - 3.5 = 25.5.

Last but not least, let's tackle the 3d electron in a copper atom. Again, Z = 29. Following the electron configuration, we group the subshells as (1s), (2s, 2p), (3s, 3p), (3d), (4s, 4p).

This time, the (3p) and (4s, 4p) groups have a total of 9 electrons. Using rule (iii), we get 9 x 0.35 = 3.15.

For the 3d electron, we also need to consider rule (v). All electrons in the n-2 shell (in this case, the (2s, 2p) group) shield completely—contributing 1.00 each. So, we add another 2 (from the (2s, 2p) group) to our S value.

Adding everything up, we get S = 3.15 + 2 = 5.15.

Now, Zeff = Z - S. Z = 29, and S = 5.15. So, Zeff = 29 - 5.15 = 23.85.

Phew! That was a lot of calculations, but I hope you're feeling less lost now. Remember, these rules are just a simplified approximation, so they're not absolute. But hey, they do the job most of the time!

Now, go forth and conquer those effective nuclear charge problems, my friend!

To calculate the effective nuclear charge (Zeff) for a valence electron in an oxygen atom, we need to determine the true nuclear charge (Z) and the shielding constant (S).

The electron configuration of oxygen is 1s^2 2s^2 2p^4, so we group the subshells as follows: (1s), (2s, 2p), (3s, 3p), (3d), (4s, 4p), (4d), (4f), (5s, 5p), and so on.

The valence electron in oxygen is in the 2p subshell. According to the empirical rules, electrons in groups to the right of the (2p) group contribute nothing to the shielding constant.

All the other electrons in the (2s, 2p) group shield the designated electron to the extent of 0.35 each.

In this case, there are 2 electrons in the 2s subshell that contribute 0.35 each. There are also 4 electrons in the 2p subshell that contribute 0.35 each.

The true nuclear charge (Z) for oxygen is 8.

Using the formula Zeff = Z - S, we can calculate the effective nuclear charge for the valence electron in oxygen:

Zeff = 8 - (2 × 0.35 + 4 × 0.35)
= 8 - (0.70 + 1.40)
= 8 - 2.10
= 5.90.

Therefore, the effective nuclear charge (Zeff) for a valence electron in an oxygen atom is approximately 5.90.

To calculate the effective nuclear charge (Zeff) for a valence electron in an atom, you can use the formula Zeff = Z - S, where Z represents the true nuclear charge and S represents the amount of shielding.

In order to determine the shielding constant (S), you can follow the empirical rules devised by John C. Slater. Here's a step-by-step guide on how to apply those rules:

1. Write the electron configuration of the element. For oxygen (O), the electron configuration is 1s² 2s² 2p⁴.

2. Group the subshells according to the Slater rules: (1s), (2s, 2p), (3s, 3p), (3d), (4s, 4p), (4d), (4f ), (5s, 5p), and so on.

3. Determine the groups of electrons that contribute to the shielding constant for the designated electron. For a valence electron in an oxygen atom, the designated electron is in the 2s orbital. Therefore, we need to consider the (1s) and (2s, 2p) groups.

4. According to rule (ii), electrons in groups to the right of the (2s, 2p) group contribute nothing to the shielding constant for the designated electron. So, we only need to focus on the (1s) and (2s, 2p) groups.

5. Apply rule (iii), which states that all the electrons in the (ns, np) group shield the designated electron to the extent of 0.35 each. In the case of oxygen, the (2s, 2p) group consists of 6 electrons (2s² 2p⁴), so they collectively contribute 6 * 0.35 = 2.1 to the shielding constant.

6. Apply rule (iv), which states that all electrons in the n-1 shell shield to the extent of 0.85 each. Since the (1s) group lies in the n-1 shell, the 2 electrons in the 1s orbital contribute 2 * 0.85 = 1.7 to the shielding constant.

7. Add up the contributions from steps 5 and 6 to obtain the total shielding constant (S): S = 2.1 + 1.7 = 3.8.

8. Finally, calculate the effective nuclear charge (Zeff) using the formula Zeff = Z - S. For oxygen, Z (the true nuclear charge) is equal to 8 (the atomic number). Therefore, Zeff = 8 - 3.8 = 4.2.

So, the effective nuclear charge for a valence electron in an oxygen atom is approximately +4.2, not +6 as you initially calculated.

You can apply a similar process to calculate Zeff for the 4s electron in a copper atom and the 3d electron in a copper atom using the corresponding electron configurations and applying the rules mentioned above.

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.