Question

A metal which is poor conductor of electricity is
A. Zinc
B. Aluminum
C. Tungsten
D. Iron

Answer 1

Hint: In order to answer this question, we should know about the properties of the conductor. Material which possess free electrons delocalized over its crystal structure conduct electricity in solids whereas in case of liquids, ions are the charge carriers that conduct electricity.

Complete answer:
As we already know that material in solid state conducts electricity when it has free or unpaired electrons. These electrons move throughout the crystal's structure and hence it conducts electricity. In liquids, the compounds which easily dissociate into cations and anions can conduct electricity.

Let’s take each example one by one;
In option A, Zinc is a d- block element, so due to the presence of free valence electrons holding the metal together electrostatically such that positively charged metal nuclei can move with respect to each other without disturbing the bonding electrons. Hence it conducts electricity.
In option B, Aluminum is a p-block element. When we see its electronic configuration, we observe that it has unpaired electrons in its valence shell. Thus, it also conducts electricity.

In option C, Tungsten is a metal even though it does not conduct electricity. It is an exceptional case, but it can conduct electricity at high temperatures.
In option D, Iron is a metal and it has metallic bonds where the electrons are free to move around more than one atom.

Therefore, tungsten is the metal which is a poor conductor of electricity. Hence, the correct answer is option C.

Note: It must be noted that even though tungsten is a metal, it is still a bad conductor of electricity. But, it has a high melting point so it can be used in the filament of bulbs. Also, it can conduct electricity at high temperatures.