Question

Q5. Define lanthanoid contraction ?. Write it’s consequences of lathanoid contraction

Answer 1

It is defined as the irregularities in Third period elements due to the poor shielding effect of 4f electrons

It's consequences are

it results in decreasing radii of elements
it results in diff. in basic properties of third period elements
it results in duff. in Ionisation enthalpy
it results in duff. in complex compounds formed by these elements.