Question

Effective nuclear charge for helium

Answer 1

The effective nuclear charge on electron is equal 1 in hydrogen atom. Helium contains two protons and two electrons. But there is not the effective nuclear charge equal 2 on each electron in helium atom, it is about 1.7 units.

Hope it is helpful....

Answer 2

Explanation:

When an electron present in a multi-electron atom experiences a net positive charge then it is known as effective nuclear charge and it is represent as $Z_{eff}$.

Formula for effective nuclear charge is as follows.

            $Z_{eff}$ = Z - S

where,      Z = number of protons in the nucleus of the atom

                 S = shielding constant

Since, we have to calculate $Z_{eff}$ for helium atom and its electronic configuration is $1s^{2}$.

So, for He atom value of S = 0.30 because the electrons are present in 1s orbital.

Therefore, calculate the effective nuclear charge for helium as follows.

                      $Z_{eff}$ = Z - S

                              = 2 - 0.30

                              = 1.7

Thus, we can conclude that the effective nuclear charge for helium is 1.7.