Down the group what is the effect on Effective nuclear charge and across the period plz explain

Dear Student

Effective nuclear charge is the charge experienced by the valence electrons of an atom taking into account the number of shielding electrons (i.e., electrons in the same atom interacting with each other). The term effective is used because the shielding effect of negatively charged electrons prevents the orbitals from experiencing full nuclear charge. The effective nuclear charge experienced by the valence electrons is always less than the total nuclear charge of an atom.

So, down the group, effective nuclear charge would decrease because of the increasing number of subshells, the shielding effect is high (because atomic radius increases down the group) which more than counters its effect. So, the electrons because loose bounded and it becomes easier to remove them.
Now, across the period, we know the first ionisation energy generally increases. This happens because more protons are now added to the nuclei of the atom, thereby resulting in an increase in their nuclear charge. Therefore, the valence electrons are then more tightly held and it becomes difficult to remove them.


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Effective nuclear charge is may be defined as force of attraction by nucleus over external shell electron again shielding effect. It is denoted by Z* where

? Z* = Z ? S

Where Z= Atomic number? S= number of electron creating Shielding effect
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No i m not asking this
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down the group the effective nuclear charge decreases as there is an increase in the number of subshells,thus the screening effect is high therefore resulting in loosly bounded electrons in the valence shell.[ increase in atomic size decrease in nuclear charge
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