The atomic radii of the elements are almost same of which series

The atomic radii of transition series elements

The atomic radii of the metals of the third (5d) series of transitions elements are virtually the same as those of the corresponding members of the second (4d) series. Explain.

The atomic radius of elements of which of the following series would be nearly the same

The atomic radius of elements of which of the following series would be nearly the same

How would you account for the following? The atomic radii of the metals of the third (5d) series of transition elements are virtually the same as those of the corresponding members of the second (4d) series.

Assertion : The order of atomic radii of Cu, Ag and Au is Cu lt Ag ~~ Au . Reason : The atomic radii of 4d series elements are larger than those of 3d series elements but generally the radii of 4d and 5d series elements are almost identical.

Assertion : The order of atomic radii of Cu, Ag and Au is Cu lt Ag ~~ Au . Reason : The atomic radii of 4d series elements are larger than those of 3d series elements but generally the radii of 4d and 5d series elements are almost identical.

In the first transition series, atomic radii of the elements from Cr to Cu remain more or less the same. Explain.