Question

why particles of a colloidal solution do not Settle Down When left undisturbed while in the case of suspension they do

Answer 1

because colloidal solution particle are smaller than suspension particle

Answer 2

In collides particles seize is between 1nm to 1000nm and they are small particles so they don't settle down but in suspension particles seize is > 1000nm so they are bidg and they settle down when left undisputed