Which of the following non-metals exists in a solid state at room temperature?

Pavan separates some materials into two groups and notes their properties. These properties are given in the table below:

Group $1$	Group $2$
They cannot be beaten into sheets.	They can be beaten into sheets.
When one end is in contact with a hot object,the other end does not get hot quickly.	When one end is in contact with a hot object,the other end gets hot quickly.
They cannot be drawn into thin wires.	They can be drawn into thin wires.

Which of the following statements cannot be false?

$A$ metal $M$ does not liberate hydrogen from acids but reacts with oxygen to give a black coloured product. Identify $M$ and the black coloured product,and also explain the reaction of $M$ with oxygen.

Which of the following is not a metalloid?

Distinguish between the following:
$(i)$ Electrolytic reduction and electrolytic refining
$(ii)$ Mineral and ore
$(iii)$ Alloys and amalgams

Which non-metal element is used in the vulcanization of rubber?