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

Which one of the following four metals would be displaced from the solution of its salts by the other three metals?

What happens when:
$(i)$ $A$ piece of calcium is dropped in water.
$(ii)$ Sodium is kept exposed in air.
$(iii)$ Iron nail is dipped in copper sulphate solution.
$(iv)$ Potassium is dropped in cold water.
$(v)$ Carbon dioxide is compressed in water at high pressure.
Give chemical equations involved in all the above reactions and balance them.

Which of the following is a mineral of sulfur?

$A$ metal that exists as a liquid at room temperature is obtained by heating its sulphide in the presence of air. Identify the metal and its ore and give the reaction involved.

Which of the following non-metals is a liquid?