Compare and contrast the size of the 1st,2nd and 3rd row transition element?

Comparing the size of 1st,2nd & 3rd row transition elements we come to know that normally 4d elements has greater atomic radius than 3d elements but there is not enough difference in size between 4d &5d elements.They are almost same in size.This is due to lanthanide contraction.Between 4d & 5d,4f is filled & the atomic radius decreases gradually.So even after addition of a new shell, the increasing of the atomic radius of 5d elements is too low.