Question

why electron are negatively charged ( quantum physics)​

Answer 1

When there is an excess of electrons, the object is said to be negatively charged. When there are fewer electrons than the number of protons in nuclei, the object is said to be positively charged.

Electric charge: −1 e; −1.6021766208(98)×10−19 C; −4.80320451(10)×10−10 esu

Antiparticle: Positron (also called antielectron)

Mass: 9.10938356(11)×10−31 kg; 5.48579909070(16)×10−4 u;−1 u; 0.5109989461...

Composition: Elementary particle

Answer 2

When an electron is far away from the nucleus,the attraction between them is little. The electron is said to be at rest and the energy is assumed to be zero.

When electrons moves towards the nucleus, energy is emitted.

ie; becomes less than zero.

That's why electronic energy is negative.