Why are proton positively charged and electrons are negatively charged?

Answer 1

During the early 20th Century, when Physicists began to succeed in investigating structure

smaller than the atom, it was discovered that the atom itself is composed of even smaller

particles, that two of the atom's constituent particles are electrically charged, and that their

charges are opposite. At that point, labels had to be invented to distinguish between the

two opposite forms of electric charge. There were many suggestions, and the choice of names

wasn't easy. They could have been called male and female charge, front and back charge,

Democrat and Republican charge, slave and free charge, old and new charge, inside and outside,

light and dark, fat and skinny, hard and soft, fast and slow, ancient and modern, Shi'ite and Sunni,

round and square charge, hot and cold charge, smart and dumb charge, etc. The choices seemed

endless. Finally, it was decided to end the debate, declare a truce, simply refer to them as

"positive" and "negative" charge, and get on with the business of studying them. The scientific

world eventually forgot all about the heated debate, the infighting, the quarreling that for a time

threatened to split Physics itself into two camps permanently at war with each other. Today

it is only the Historians of Science, such as Dr. R. E. Selya of Harvard and UCLA, who recall

that perhaps in a parallel universe, and for a moment even in our own, we might have ended up

with Harry and Sally, Bonny and Clyde, or Itchy and Scratchy, for our static electric charges.

Answer 2

Protons are positively charged due to their composition of two up quarks and one down quark, which carries positive electric charge. Electrons are negatively charged because they are fundamental particles with a negative charge, and they do not have smaller constituents with a positive charge.