Identify the cations and anions present (if any) in the following compounds:
$(a)$ $CH_3COONa$
$(b)$ $NaCl$
$(c)$ $H_2$
$(d)$ $NH_4NO_3$

$(a)$ Write the chemical symbols of two elements:
$(i)$ which are formed from the first letter of the element's name.
$(ii)$ whose name has been taken from the names of the elements in Latin.
$(b)$ Define Avogadro's constant and molar mass. How are they related to one mole of an atom,molecule,or ion?

State whether the following statement is true or false:
Oxygen molecules exist in the form of three molecules as $O_{2}$,$O_{3}$,and $O_{4}$.

Write the chemical formulae and names of the compounds formed by the combination of:
$(i)$ $Fe^{3+}$ and $SO_{4}^{2-}$
$(ii)$ $NH_{4}^{+}$ and $CO_{3}^{2-}$

Derive the molecular formula for Ammonium carbonate.

$(a)$ Define atomicity.
$(b)$ State the atomicity of the following molecules:
$(i)$ Oxygen,$(ii)$ Phosphorus,$(iii)$ Sulphur,$(iv)$ Argon.