Electron is negatively charged came to our knowledge when J.J Thomson discovered sub atomic particles in an atom naming it as an electron. The electron is always depicted with a negative kind of charge and in order to understand why it is negatively charged, you need to do nothing but study the same what was practiced by J.J Thomson. It was Cathode Ray Experiment. I won’t ask you to go for the CRT experiment on your own but you may simply study the experimented results of it to understand it in a better way.
Why Electron Is Negatively Charged
1. What The C.R.T Experiment Demonstrates:-
In the Cathode Ray Tube experiment, the rays were emitted at cathode part of a discharge tube. This one is the part that has got cations with it. The negatively charged particles which were repelled in this experiment were attracted to the anode which is having anions with it. This makes us have a conclusion that the rays must be negatively charged. The cathode ray experiment was just a start but it followed many other researches and researchers that concluded the fact that electron are negatively charged.
2. The Conclusions That Rutherford Made:-
Rutherford studies again the same what had been demonstrated by J.J Thompson and he was sure about the fact that there must also be some positively charged particles within the atom to balance the negative electrons. These positively charged particles were discovered by Rutherford and named as protons.
3. How Rutherford Made His Experiment:-
This was made by him through the gold foil experiment which included the bombardment of rays over it and the way some of the particles got deflected made it sure that there must be something for sure that is preventing the rays from passing straight and when these get deflected it means there is something as an obstacle for sure.
4. Why The Conclusion That Electron Is Negatively Charged:-
The positive and negative charges are based on the fact if there is an attraction or repulsion felt within these experiments and as we know that in case there is one positive and one negative, they will get attracted and thus this is kept in consideration while concluding if the charge will be negative or positive over an electron. The further studies were made by the researchers that arrived afterwards and made researches based on the same and thus a conclusion was made that electron is negatively charged.