The sizes of the second and third row transition elements being almost the same . This is due to :

Sizes of the seond and third row transition elements are almost the same because of

The atomic radii of the second and third transition series are almost the same. Why?

The first elements of first second and third transition series respectively are

The second and third rows of transition elements resemble each other much more than resemble the first row. Explain why ?

The second and third rows of transition elements resemble each other much more than they resemble the first row. Explain, why?

The second and third rows of transition elements resemble each other much more than they resemble the first row. Explain, why?