Question

Metals are lustrous.
[A] True
[B] False

Answer 1

Hint: Metals are chemical elements and occupy one fourth of the Earth’s crust. They are good conductors of electricity and thus have free electrons in them. The electrons absorb light but reflect back more than what they have absorbed.

Complete step by step answer:
 Metals are chemical elements that comprise 25% of the Earth’s crust. Metals have certain properties that make them different from other elements. Let us discuss some of the properties of metals-
- Metals are malleable i.e. they can be hammered into thin sheets and ductile i.e. they can be drawn into thin wires.
- Metals mix with other metals and form alloys.
- Metals have high density and are good electrical and thermal conductors.
- Metals are lustrous i.e. they have a shiny appearance.
- Metals have closely packed structures and low electronegativity.
- Examples of metals are gold, silver, copper, platinum etc. In the periodic table, we have alkaline earth metals, alkali metals, transition metals etc.
We can understand from the above discussion that lustre is a property of metals.
As we have discussed above, metals are good conductors of electricity, which means they have free electrons in them. Due to the presence of these free electrons, the light coming to the surface is absorbed to some extent but the rest is reflected back as the electrons get excited. This makes the metals lustrous.
So, the correct answer is “Option A”.

Note: There are some elements that act like metals at certain pressure conditions. Iodine is a non-metal but at a pressure 70 to 140 thousand times the atmospheric pressure it acts like a metal. There are also some metals that lose metallic properties at certain pressure conditions. Sodium is a metal but at a pressure 2 million times under the atmospheric pressure, it becomes a non-metal.