Which of the following is a compound?

What are metalloids? Give examples.

Classify each of the following as a physical or a chemical change. Give reasons.
$(a)$ Drying of a shirt in the sun.
$(b)$ Rising of hot air over a radiator.
$(c)$ Burning of kerosene in a lantern.
$(d)$ Change in the colour of black tea on adding lemon juice to it.
$(e)$ Churning of milk cream to get butter.

How is heating of sugar and heating of ammonium chloride different from each other? Explain your answer.

Non-metals are usually poor conductors of heat and electricity. They are non-lustrous,non-sonorous,non-malleable,and are coloured.
$(a)$ Name a lustrous non-metal.
$(b)$ Name a non-metal which exists as a liquid at room temperature.
$(c)$ The allotropic form of a non-metal is a good conductor of electricity. Name the allotrope.
$(d)$ Name a non-metal which is known to form the largest number of compounds.
$(e)$ Name a non-metal other than carbon which shows allotropy.
$(f)$ Name a non-metal which is required for combustion.

How are mixtures different from compounds?