The density of elements belonging to the 3rd transition
series is double that of the elements belonging
to the 2nd transition series procided they are
in the same group unlike alkali and alkaline earth
metals. Comment.

Explanation

(i) factors affecting density
(ii) general trend of atomic sixes in groups of
transition elements
(iii) effect of inclusion of lanthanide elements on
the atomic size of the elements belonging to
the 3rd transition series
(iv) factors affecting the density of an atom
(v) change in atomic size of alkali and alkaline
earth metals along the group
(vi) comparison of chanog of densities along the
group among alkali, alkaline earth and transition
metals