Question

The general electronic configuration $\left( {{\text{n - 1}}} \right){{\text{d}}^{\text{3}}}{\text{n}}{{\text{s}}^{\text{2}}}$ indicates that particular element belongs to:
A.VB
B.IVB
C.VIB
D.IIIB

Answer 1

Hint: Electronic configuration is a representation of the distribution of electrons in an atom. A d-block element has partially filled d subshell in its elementary or ionic state and the last electron enters the $\left( {{\text{n - 1}}} \right){\text{d}}$ orbital, i.e., the last electron enters the penultimate (last but one) shell.
 The general electronic configuration of d – block elements is $\left( {{\text{n - 1}}} \right){{\text{d}}^{1 - 10}}{\text{n}}{{\text{s}}^{{\text{0 - 2}}}}$ where n represents the outermost shell.

Complete step by step answer:
The d – block elements are also known as transition elements and they lie in between s and p block elements in the long form of the periodic table. This means the d – block elements constitute the elements of the groups 3 to 12.
The properties of d – block elements lie between those of s and p block elements. They are called d – block elements as the 3d, 4d, 5d and 6d subshells in these elements are incomplete.
The electronic configurations of the d – block elements have the following characteristics.
They have an inner core of electrons with noble gas configuration. The $\left( {{\text{n - 1}}} \right){\text{d}}$ orbitals are progressively filled up with electrons. Most of them have 2 electrons in the outermost shell ‘ns’.
Now, the electrons are added to the d subshell successively from group 3 to 12.
So, the general electronic configuration of group 3 d-block elements will be $\left( {{\text{n - 1}}} \right){{\text{d}}^1}{\text{n}}{{\text{s}}^{\text{2}}}$ and the general electronic configuration of group 4 d-block elements will be $\left( {{\text{n - 1}}} \right){{\text{d}}^2}{\text{n}}{{\text{s}}^{\text{2}}}$ . Proceeding in this way, we get the general electronic configuration of group 5 d-block elements will be $\left( {{\text{n - 1}}} \right){{\text{d}}^3}{\text{n}}{{\text{s}}^{\text{2}}}$ . Since group 5 is also called group VB,

Hence the correct option is A.

Note:
-The d – block elements are classified into horizontal series. There are 4 main transition series of elements corresponding to the filling of the 3d, 4d, 5d and 6d sublevels in the fourth, fifth, sixth and seventh periods.
-The first transition series or the 3d series corresponds to the filling of the 3d sublevel, the second transition series or the 4d series corresponds to the filling of the 4d sublevel, the third transition series or the 5d series corresponds to the filling of the 5d sublevel and the fourth transition series or the 6d series corresponds to the filling of the 6d sublevel.