Question

In d-Block when atomic size of one series are compared with those of corresponding element in other series:
I.) Increase from the first (3d) to second (4d) series
II.) Increase from second (4d) to third (5d) series
III.) Virtually the same as first (3d) and second (4d) series
IV.) Virtually the same as second (4d) and third (5d) series
a.) I, II
b.) I, III
c.) II, III
d.) None

Answer 1

Hint: d-block elements are those elements whose outermost electron is present in d orbital. Generally d-block elements are known as transition elements.

Complete step by step answer:
The elements that have incompletely filled d-subshell in their ground state or most stable oxidation state are termed as d-block elements. They can also be known by transition elements. The partially filled subshells incorporate the (n-1) d subshell. All the d-block elements have a similar number of electrons in the furthest shell. The d-block elements consist of three series called as 3d-(first series) Sc-Zn, 4d series (second series) Y-Cd and the 5d series (third series) La-Hg separately. Ten elements are present in each series.
Atomic size trend: Atomic size increases with the increase in the number of shells so atomic size of 4d series is more than that of 3d series. But the atomic size of 4d and 5d series remains due to lanthanoid contraction. Hence we can say that atomic size increases from the first 3d to 4d series and virtually the same as the second and third transition series. But no choice contains (i) and (iv) options together so the option d none is correct.
So, the correct answer is “Option D”.

Note: Rather than 3d, 4d and 5d series there is also 6d series in which 7 elements are there whose first element is actinium (Ac) and other elements are from inner transition series called f-block series (Rf to Mt).