Answer:

The Correct Answer for **Calculate zeff for the 4s electron in a copper atom, cu.**

I presume that you are employing Slater’s rules for effective nuclear charge. The general idea is to subtract the effect of shielding from the genuine nuclear charge, Z . The formula for s and d electrons is different, but it has the same number of protons as copper, Z = 29.

If you need to store the information in electron configurations for future reference, it is recommended that you write them out on paper.

Cu: 1s2 2s2 2p6 3s2 3p6 3d10 4s1

For the 4s electron:

29 – [18(0.85) + 10(1.0)] = 3.7

For the 3d electron:

29 – [9(0.35) + 18(1.0)] = 7.85

The 4s electron has a lower-than-average atomic charge, so it has a higher probability of being destroyed than the 3d electron, should the copper ion become dissociated.

Zeff is the effective nuclear charge that is the force that a nucleus apply to the electron

we can write it as

Zeff= Z-S

here Z is the Atomic number of the element

S is shielding constant

For Cu atom

Z will be 29

and configuration will be

1s2 2s2 2p6 3s2 3p6 3d10 4s1

So the electrons with the same group shield will be 0.35

the electrons with n-1 group shield will be 0.85

the electrons with n-2 or lesser group shield will be 1

so, Zeff for 4s electron will be

Zeff= 29 – ( 18(0.85) + 10(1.0) )

Zeff = 3.7

Zeff for the 4s electron in a copper atom, cu will be 3.7.