how to find the screening effect and then the effective nuclear charge.
Answers
Explanation:
There is a formula to find screening effect. It is (0.35*no.of valence electron excluding test electron)+(0.85*no.of d (n-1) electrons)+(1.0* remaining electron)
effective nuclear charge is found by formula
Z* =Z-value of screening effect
where Z* is effective nuclear charge and Z is atomic number
Answer:
(i) Screening effect : The inner shell electrons in an atom screen or shield the outermost valence electrons from the nuclear attraction. This effect is called screening effect or shielding effect. The magnitude of screening effect depends upon the number of inner electrons. Higher the number of inner electrons, greater is the value of screening effect. The screening constant is represented by 'o' (sigma). For example, across a period the electrons enter the same shell. Thus, shielding due to inner electrons remain same. Down a group, a new larger valence shell is added which increases the inner electrons and thus the shielding effect increases
(ii) Effective nuclear charge : Due to screening effect the valency electrons experience less attraction towards nucleus. This reduces the active nuclear charge (z) actually present on the nucleus. This reduced nuclear charge is termed as 'effective nuclear charge. (Z_eff).