Question

Element having electronic configuration
$1{s^2},2{s^2},2{p^6},3{s^2},3{p^6},3{d^{10}},4{s^2},4{p^6},4{d^{10}},5{s^2},5{p^3}$ belongs to the group in the periodic table:
A.3rd A group
B.2nd A group
C.5th A group
D.7th A group

Answer 1

To answer this question, you must recall the periodic properties and the arrangement of elements in the periodic tables. The number of shells present in the atom denotes the period of the atom whereas the electrons present in the valence shell give the group number.

Complete answer:
The modern periodic table has 18 groups and 7 periods in which the atoms are arranged in the increasing order of their atomic numbers which denote the number of electrons in the element. The number of electrons, specially the valence electrons, decides all the chemical properties of a certain atom.
In the question, the given element has five shells and thus belongs to the fifth period of the periodic table. Its valence shell or the outermost shell is the fifth shell. We can see that the $5p$ orbital is half filled and $5s$ and $4d$ orbitals are fully filled. Thus, the given element is a p- block element.
For a p- block element, the group number is equal to the (10 + number of valence electrons), where the number 10 includes the $d -$block.
Number of valence electrons of the given element is 5. Thus, the group number of the element is given as $10 + 5 = 15$ or ${\text{V A}}$group.

Thus, the correct answer is C.

Note:
The periodic table can be used to derive relationships between various physical and chemical properties and behaviours of elements. The modern periodic table works as an essential framework which helps in the analysis of various chemical reactions, and is used widely in the fields of chemistry, nuclear physics and other sciences.