I need help asap 5th grade science

According to coulomb's law, how would the electrical force between particles change if the product of their electrical charge increased?

In the millikan oil drop experiment they determined that every drop had a charge which was a while number multiple of -1.60x10^-19. if a drop has a total charge of -9.60x10^-19 then how many excess electrons are contained within the drop?

Salt in oceans comes from and of rocks