Question

What is the effective nuclear charge of highest energy electron of Cs (==55) ?​

Answer 1

EFFECTIVE NUCLEAR CHARGE

The ability to attract the negative electrons around the orbits of the nucleus by the measure of the number of protons in the nucleus is known as Effective Nuclear Charge.

Electrons are attracted to the protons of the nucleus as they are negatively charged but in some cases, the inner electrons may negate the attraction of the nucleus on the outermost electrons, therefore the net attraction of these outer electrons is known as an effective nuclear charge.

CALCULATE THE EFFECTIVE NUCLEAR CHARGE OF CAESIUM

• Caesium has the atomic number 55.
• The electronic configuration is $6s^{1}$.
• The formula for calculating effective nuclear charge is

                     $Z_{eff}$ = Z - S

        Where Z= nuclear charge (number of protons)

                      S= shielding electrons

• Therefore, we have

                       $Z_{eff}$ = 55 - 54

                               = +1

ANSWER:- The effective nuclear charge of highest energy electron of Cs is +1.