The chemical symbol for sodium is

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

The atomic numbers of three elements $A, B$ and $C$ are $9, 10$ and $13$ respectively. Which of them will form a cation?

Which of the following symbols of elements are incorrect? Give their correct symbols:
$(a)$ Cobalt $CO$
$(b)$ Carbon $c$
$(c)$ Aluminium $AL$
$(d)$ Helium $He$
$(e)$ Sodium $So$

Define Avogadro's constant. How is it related to a mole?

Calculate the number of atoms in:
$(i)$ $0.02$ moles of carbon
$(ii)$ $30$ grams of carbon
$(iii)$ $6$ moles of aluminium ions.