Question

Select a lustrous material out of the following substances.
Gold, Sand, Silver, Rubber

Answer 1

Hint: To answer this, remember that luster is a property of metals. Lustrous materials are those materials that have shiny surfaces. Non-lustrous materials are those materials that do not have shine on their surfaces.

Complete step by step answer:
Firstly, let us discuss what lustrous materials are and then we can find the answer to the given question.
The term lustrous means shiny. It is the property of metals. We know that all the metals have free electrons. The free electrons can pass freely through atoms of metal which make light reflect evenly off the surface and thus the surface of metals appear lustrous. However, we must remember that metals are lustrous after polishing.

Now, let us see the given question.
Here, we have gold, silver, sand and rubber. We know that gold and silver here are metals and sand and rubber are non-metals. So, gold and silver will have a lustrous shine.
Therefore, the correct answer is gold and silver.

Note: Luster is one of the properties of metals that make them different from non-metals and minerals. Metals are chemical elements that comprise 25% of the Earth’s crust. Metals have certain properties that make them different from other elements.
- 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 due to the presence of free electrons.
- 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.