$A$ metal $P$,when exposed to moist air for a longer period of time,loses its shiny brown surface and gains a green coat. Why has this happened? Identify the metal. Write the name and chemical formula of this green-coloured compound. List two ways to prevent this process.

(N/A) $(i)$ The metal has undergone corrosion.
$(ii)$ The metal is copper $(Cu)$.
$(iii)$ The green coating is basic copper carbonate,with the chemical formula $CuCO_{3} \cdot Cu(OH)_{2}$.
$(iv)$ Two ways to prevent this process are:
$1.$ Coating the metal surface with paint or oil/grease to prevent contact with moist air.
$2.$ Alloying the metal to increase its resistance to corrosion.