Newton's law of gravity Coulomb's law Check sign. Not really the case for mass.
Fundamental particles are the basic building blocks of matter, carry mass and charge.
Well established by Millikan in 1909. From the Bohr model, the separation between the two particles is 0.53 x 10 -10 m. At the atomic level, one may typically ignore gravitational forces. Given such strong electrical interactions, atoms tend to remain uncharged. Matter prefers to be electrically neutral.