Mass of one atoms of oxygen $ = \frac{{16}}{{6.023 \times {{10}^{23}}}} = 2.66 \times {10^{ - 23}}\,g$

Mass of $6.023 \times 10^{23}$ atoms of nitrogen $= 14\,g$

Mass of one atom of nitrogen 

$ = \frac{{14}}{{6.023 \times {{10}^{23}}}} = 2.32 \times {10^{ - 23}}\,g$

Mass of $1 \times 10^{10}$ mole of oxygen $= 16 \times 10^{-10}$

Mass of $1$ mole of copper $= 63\,g$

Mass of $1$ mole of oxygen $= 16\,g$

Mass of $1 \times 10^{-10}$ mole of copper

                                                      $= 63 \times 1 \times 10^{-10}$

                                                      $= 63 \times 10^{-10}$

So, the order of increasing mass is

$II < I < III < IV$