Question

Which of the following metals does not conduct electricity?
A.Brass
B.Barium
C.Boron
D.Bismuth

Answer 1

Hint: To solve this question, we must first write down the atomic numbers and then the electronic configurations of the given elements. On the basis of the number of electrons present in the valence shell, we can determine which metal would not conduct electricity.

Complete Step-by-Step Answer:
Before we move forward with the solution of the given question, let us first understand some important basic concepts.
Every given atom has a set number of protons, neutrons and electrons. On the basis of Aufbau’s principle and Pauli’s exclusion principle, we can configure the electrons to certain energy states referred to as shells. The number of electrons present in the last shell or the valence shell of the atom determines the nature of the compound, i.e. whether it is a metal, non – metal or a metalloid. The number of electrons in the valence shell also determines the ability of an atom to conduct electricity. If the number of electrons in the valence shell is less than half of its capacity, then it has the electrons that can move about freely. When a potential is applied across such a material, the free electrons from such atoms tend to flow from higher potential to lower potential. This flow of electrons results in the formation of electricity. The ability of the atom to have freely flowing electrons is thus related with the ability of the atom to conduct electricity.
Now, the electronic configuration of the given elements can be given as:
1.Brass: Brass is an alloy of copper and zinc. Both these metals are good conductors of electricity. Since brass is an alloy of two good conductors, then it too is a good conductor of electricity.
2.Barium: the electronic configuration of Barium is \[[Xe]6{s^2}\] . Thus, Barium has only 2 electrons in the valence shell and it hence a good conductor of electricity.
3.Boron: the electronic configuration of boron is \[[He]2{s^2}2{p^1}\] . Thus, Boron has only 3 electrons in the valence shell and it hence a good conductor of electricity.
4.Bismuth: the electronic configuration of bismuth is \[[Xe]4{f^{14}}5{d^{10}}6{s^2}6{p^3}\] . Hence the valence orbital, i.e. 6p is half filled. This increases the stability of bismuth and hence it prevents the atom from releasing any free electrons. Hence, bismuth is a bad conductor of electricity.
Hence, bismuth does not conduct electricity.

Hence, Option D is the correct option

Note: Bismuth is hard, brittle, lustrous, and coarsely crystalline. It can be distinguished from all other metals by its colour—grey-white with a reddish tinge.