What is the mass of one mole of oxygen atoms (in $g$)?

Which of the following contains the maximum number of molecules?

Which has more number of atoms?
$(i)$ $100 \, g$ of $N_2$
$(ii)$ $100 \, g$ of $NH_3$

Which of the following compounds contain polyatomic ions?
$NaOH, NaCl, Na_{2}O, NaNO_{3}$

The unit accepted for measuring the mass of an atom and a molecule is

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