JEE MAIN - Chemistry (2006 - No. 40)
Lanthanoid contraction is caused due to :
the appreciable shielding on outer electrons by 4f electrons from the nuclear charge
the appreciable shielding on outer electrons by 5d electrons from the nuclear charge
the same effective nuclear charge from Ce to Lu
the imperfect shielding on outer electrons by 4f electrons from the nuclear charge
설명
The main reason of lanthanide contraction is, poor shielding of 4f electrons on the outer most shell electrons. As f orbital is defused nature so shielding of 4f electron is imperfect that is why nucleus can attract outer most shell electron easily and the size of atom decreases.
In lanthanides, there is poorer shielding of $$5d$$ electrons by $$4f$$ electrons resulting in greater attraction of the nucleus over $$5d$$ electrons and reduction of the atomic radii.
In lanthanides, there is poorer shielding of $$5d$$ electrons by $$4f$$ electrons resulting in greater attraction of the nucleus over $$5d$$ electrons and reduction of the atomic radii.