If copper is kept open in air,it slowly loses its shining brown surface and gains a green coating. It is due to the formation of

Generally,non-metals are not lustrous. Which of the following non-metal is lustrous?

$A$ non-metal $A$ is an important constituent of our food and forms two oxides $B$ and $C$. Oxide $B$ is toxic,whereas $C$ causes global warming.
$(a)$ Identify $A$,$B$,and $C$.
$(b)$ To which Group of the Periodic Table does $A$ belong?

What happens when a glass rod dipped in concentrated hydrochloric acid is brought near a container filled with ammonia gas?

Which of the following gases is combustible?

Name the following:
$(a)$ $A$ metal which is preserved in kerosene.
$(b)$ $A$ lustrous coloured non-metal.
$(c)$ $A$ metal which can melt while kept on palm.
$(d)$ $A$ metal which is a poor conductor of heat.