There is a large group of materials P which can be divided into three groups Q, R and S on the basis of their properties. The substances belonging to group Q can be solids, liquids or gases. The solids belonging to group Q are usually electrical insulators. Most of the substances of group R are solids which are good conductors of electricity. The substances belonging to group S are neither insulators like Q nor good conductors like R. The properties of S are intermediate between those of Q and R.
(a) What could the group of materials P be?
(b) Name the substances Q. Give two examples of such substances.
(c) Name the substances R. Write two examples of such substances.
(d) Name the substances S. Give two examples of such substances.
(e) Out of Q, R and S, which substances are malleable and ductile?