Question

Non-metals are usually poor conductors of heat and electricity. They are non-lustrous, non-sonorous, non-malleable and are coloured. Name a non-metal other than carbon which shows allotropy.

Answer 1

Hint: Here, you are asked to name a non-metal which shows allotropy. First thing you need to know is, what is allotropy. After giving a thought on allotropy, think which non-metals can be considered as elements who show this property. There are a number of elements who can show allotropy but you should only consider those elements that are non-metals, that is why you are given a small description in the beginning of the question about non-metals.

Complete answer:
If an element can exist in two or more different forms physically, this property is called allotropy. A non-metal that can show allotropy is Sulphur. It is non-metal and is a poor conductor of both heat and electricity. It is non-lustrous, non-malleable and is coloured.Hence, a non-metal other than carbon which shows allotropy is Sulphur.

Additional Information:
Non-metals are usually poor conductors of heat and electricity. As you know, metals have free electrons in them which can move freely and help the metal to conduct electricity and heat. Since, there is a shortage of free electrons in non-metals, they do noy conduct heat and electricity. Non-lustrous means that they are dull, their surface is not shiny.

As non-metals are usually not solids and do not have crystalline surface and are also unable to form flat surface, they are non-lustrous. Metals are malleable and can be beaten to form a thin sheet but non-metals are brittle and can be broken easily and hence are non-malleable.

Note: It is to be noted that Sulphur is not the only non-metals which shows allotropy. There are other non-metals which can show allotropy such as phosphorus and oxygen, so, this thing you should keep in your mind. Also, remember the definitions of various terms used in this question, such as conductivity, lustrous, malleability and sonorous.