Question

The extent of actinoid contraction is greater than lanthanoid contraction explain.

Answer 1

In lanthenoid $4f$ orbital is present in low lying level while in actinoids $5f$ orbital is there. As $5f$ orbital has poor shielding value than $4f$ orbital
$\therefore$ $Z_{eff}$ = z- $\sigma$
($\sigma$ is shielding constant ) is more for $5f$ than $4f$. More the $Z_{eff}$ more will be contraction in size. $\therefore$ actinoid contraction is more than lanthenoid contraction.