Hello anisayati,
Lets pretend that both particles are spherical and have the same density.
A smaller sized particle will have less pore spaces, so the exposed surface area should increase (large particle ~60 m2/g, nano particle 600 m2/g).
The trick here is the weight.. My previous statement said the same density.
Could you look up the density of these two components. I am guessing that one will be significantly more dense than the other.
I am looking forward to your response.
Sincerely,
Eugene