Final answer:
The effective nuclear charge (Zeff) for a 3d electron in a copper atom (Cu) can be estimated using the formula Zeff = Z - S, where Z is the atomic number of copper (29) and S is the shielding constant due to the electrons in inner shells (18 core electrons from the [Ar] configuration). Therefore, Zeff for a 3d electron in copper is approximately +11e.
Step-by-step explanation:
To calculate the effective nuclear charge (Zeff) for a 3d electron in a copper atom (Cu), we need to consider the atomic number of copper (Z) and the electrons that contribute to shielding. The atomic number of copper is 29, which means there are 29 protons in the nucleus.
The shielding effect is mostly due to the electrons in the inner shells. For a 3d electron in copper, the inner shells contribute to the shielding. Copper's electron configuration is [Ar]3d104s1, indicating that there are 18 core electrons from the [Ar] noble gas configuration and the 3d10 electrons that also shield the 4s electron. However, since we are interested in a 3d electron, we will not count these 10 electrons in the shielding since they are on the same energy level.
According to the equation Zeff = Z - S, where Z is the atomic number and S is the shielding constant, we first approximate S. In this case, S is the number of shielding electrons, which is 18. So, the effective nuclear charge of the 3d electron in a copper atom can be approximated as follows: Zeff = 29 (atomic number of Cu) - 18 (shielding electrons) = 11.
Thus, the effective nuclear charge experienced by a 3d electron in a copper atom is approximately +11e.