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

Which of the following postulates of Dalton's atomic theory is challenged by the next generation of scientists?

State whether the following statement is true or false:
$A$ mole always represents $6.023 \times 10^{22}$ atoms,molecules,or ions of a substance.

Write the chemical names of the following compounds:
$(a)$ $K_{2}SO_{4}$
$(b)$ $Mg_{3}(PO_{4})_{2}$
$(c)$ $NH_{4}Cl$
$(d)$ $ZnS$
$(e)$ $Na_{3}N$
$(f)$ $AgBr$

$A$ chlorine atom is electrically neutral,but a chloride ion is a charged ion. Explain.

Fill in the blanks:
$(a)$ In a chemical reaction,the sum of the masses of the reactants and products remains unchanged. This is called ...............
$(b)$ $A$ group of atoms carrying a fixed charge on them is called ...............
$(c)$ The formula unit mass of $Ca_3(PO_4)_2$ is ...............
$(d)$ The formula of sodium carbonate is ............... and that of ammonium sulphate is ...............