Question

The electronic configuration of only one p-block element is exceptional. One molecule of that element consists of how many atoms of it?
(A) one
(B) two
(C) three
(D) four

Answer 1

Hint: The elements in which the last electrons enter the outermost p-orbital belong to p-block elements. The maximum number of electrons in p orbitals is six and p-block elements with six groups in the periodic table. Group 13 to 18 numbering in the periodic table of p-block elements.

Complete step by step solution:
The valence shell electronic configuration of p-block elements is $n{{s}^{2}}n{{p}^{1-6}}$ . there are six groups in p-block elements from group 13-18 are boron, carbon, nitrogen, oxygen, fluorine, and helium elements are head the groups respectively.
The elements in group 18 are called noble gases. The elements in the group are helium (He), neon (Ne), Argon (Ar), krypton (Kr), Xenon (Xe), and radon (Rn). The valence shell electronic configuration of this group element is $n{{s}^{2}}n{{p}^{6}}$ . All noble gases in this group obey this electron configuration except Helium (He). Because the electronic configuration of helium is $1{{s}^{2}}$ .
So, this is an exceptional case not only in this group also in p-block elements. This helium does not follow the trend in p-block elements electronic configuration and He is a noble gas. So this is monoatomic gas.
Hence, the Electronic configuration of only one p-block element is He and the element consists of one atom due to monoatomic gas.

The correct answer is option A.

Note: Only p-block elements exist with both nonmetals and metalloids in the periodic table. The non-metallic character decreases down the group in p-block elements. The interesting thing is the heaviest metal in each p-block element group is the most metallic nature.