Question

The elements $\text{N}$, $\text{P}$, $\text{As}$, $\text{Sb}$, and $\text{Bi}$ belong to :
A.VA group
B.IV A group
C.VII A group
D.VIII A group

Answer 1

The modern periodic table is arranged into eighteen groups and eight periods while the Mendeleev’s periodic table consisted of eight groups, arranged in different subgroups.

Complete step by step answer:
The electronic configurations of the elements given in the question are:
$\text{N}$- $\text{1}{{\text{s}}^{\text{2}}}\text{2}{{\text{s}}^{\text{2}}}\text{2}{{\text{p}}^{\text{3}}}$,
$\text{P}$- $\text{1}{{\text{s}}^{\text{2}}}\text{2}{{\text{s}}^{\text{2}}}\text{2}{{\text{p}}^{6}}\text{3}{{\text{s}}^{\text{2}}}\text{2}{{\text{p}}^{3}}$,
$\text{As}$- $\text{3}{{\text{d}}^{\text{10}}}\text{4}{{\text{s}}^{\text{2}}}\text{4}{{\text{p}}^{3}}$,
$\text{Sb}$- $\text{4}{{\text{d}}^{\text{10}}}\text{5}{{\text{s}}^{\text{2}}}\text{5}{{\text{p}}^{3}}$,
$\text{Bi}$- $\text{4}{{\text{f}}^{\text{14}}}\text{5}{{\text{d}}^{10}}\text{6}{{\text{s}}^{\text{2}}}\text{6}{{\text{p}}^{3}}$.
In all the configurations, the valence shell of the element has five electrons and as the group number is decided by the number of valence shell electrons, hence the elements have group number V A group. The V B subgroup was kept mainly for the transition metals with five electrons in the d-orbitals.

So, the correct answer is option A.

Note:
Mendeleev’s periodic table is based on the periodic law that the properties of the elements are periodic functions of their atomic weights while the Modern periodic law is dependent on the modern periodic law which states that the properties of the elements are periodic functions of their atomic numbers. This is because of the discovery of the isotopes which are the atoms of the elements with the same number of electrons but different numbers of neutrons. There were many discrepancies with the Mendeleev’s periodic law and hence the modern periodic law was devised.
The period number is decided by the orbital number that is being filled as the valence shell.