Name the elements represented by the following symbols:
$(a)$ $Au$
$(b)$ $Ag$
$(c)$ $Hg$
$(d)$ $Sn$

$(a)$ Define the following:
$(i)$ Mole
$(ii)$ Gram atomic mass
$(iii)$ Gram molecular mass
$(b)$ Calculate the mass of the following:
$(i)$ $2$ moles of carbon dioxide
$(ii)$ $6.022 \times 10^{23}$ molecules of carbon dioxide.

Determine the atomicity of the following molecules:
$(i)$ $H_{2}SO_{4}$
$(ii)$ $CCl_{4}$

The molecule having an atomicity of $4$ is

Write the names of the compounds represented by the following chemical formulae:
$(i)$ $NaBr$
$(ii)$ $Al_{2}O_{3}$
$(iii)$ $Zn(NO_{3})_{2}$
$(iv)$ $HCl$
$(v)$ $NaCl$
$(vi)$ $CaCO_{3}$

Verify by calculating that:
$(a)$ $5 \, mol$ of $CO_2$ and $5 \, mol$ of $H_2O$ do not have the same mass.
$(b)$ $240 \, g$ of calcium and $240 \, g$ of magnesium elements have a mole ratio of $3:5$.