Why is there an increase in the atomic radius of transition elements at the end of the period?

Which of the following element belongs to the second transition series of the periodic table?

Which of the following element is not a transition element?

Which of the following is the correct order of arrangement of the first five lanthanides according to atomic number?

What is the formula of hematite?

The main factor for the cause of lanthanide contraction is poorer shielding of 5d electrons by 4f electrons.

What is the common oxidation state of scandium? (At. No. of Sc = 21)

The study of transition elements is useful.