Calculate zeff for the 4s Electron in a copper Atom, cu.

A. 2.2

B. 2.95

C. 1.0

D. 1.65

Answer:- A. 2.2

The correct answer is 2.2. The effective nuclear charge (Z*) is the net positive charge experienced by an electron in an atom. It is calculated as follows:

Z* = Z – S

where:

Z is the atomic number of the atom

S is a shielding constant that takes into account the effects of inner electrons

For copper, the atomic number is 29. The shielding constant for the 4s electron is calculated using Slater’s rules, which give a value of 2.8. Therefore, the effective nuclear charge for the 4s electron is:

Z* = 29 – 2.8 = 2.2

This means that the 4s electron in copper experiences a net positive charge of 2.2. This is less than the full nuclear charge of 29 because the inner electrons shield the 4s electron from the full force of the nuclear charge.