The ratio of the electrostatic force of attraction to the gravitational force between the proton and electron of the hydrogen atom is of the order of

Electrostatic force of attraction $=\frac{k{q}_1{q}_2}{r^2}$

$=\frac{9\times 10^9\times (1\cdot 6\times 10^{-19}{)}^2}{r^2}$
Gravitational force of attraction $=\frac{G{m}_e{m}_p}{r^2}$

$=\frac{(6\cdot 67\times 10^{-11})(9\cdot 1\times 10^{-31})(1\cdot 67\times 10^{-27})}{r^2}$

$Ratio\frac{F_e}{F_g}=\frac{9\times 10^9\times (1\cdot 6\times 10^{-19}{)}^2}{(6\cdot 67\times 10^{-11})(9\cdot 1\times 10^{-31})(1\cdot 67\times 10^{-27})}$

$=\frac{23\cdot 04\times 10^{-29}}{101\cdot 36\times 10^{-69}}$

$=2\cdot 27\times 10^{39}$