$(a)$ Compare metals and non-metals based on their physical properties. (any four points)
$(b)$ What are metalloids? Give two examples.
$(c)$ Identify metals from the following: Boron,sodium,mercury,carbon.

(C) Comparison between metals and non-metals:

Metals	Non-metals
$(1)$ Metals are malleable and ductile.	$(1)$ Non-metals are brittle.
$(2)$ Metals are sonorous,i.e.,they produce a ringing sound when struck.	$(2)$ Non-metals are not sonorous.
$(3)$ Metals are good conductors of heat and electricity.	$(3)$ Non-metals are poor conductors of heat and electricity (except diamond and graphite).
$(4)$ Metals are generally solids at room temperature (except mercury).	$(4)$ Non-metals can be solids,liquids,or gases at room temperature.

$(b)$ Elements that exhibit properties intermediate between those of metals and non-metals are called metalloids. Examples: Boron $(B)$ and Silicon $(Si)$.
$(c)$ Among the given elements,sodium $(Na)$ and mercury $(Hg)$ are metals.