Question

How rutherford knew that mass of atom was concentrated?

Answer 1

Answer:

1. he sent alpha rays( positive )in thin gold foil inwhich only few came back all passes away this indicates that only where elections r there in that place it attracts
2. but in nucleus only + ve charge is available it repels
3. so that repelling part is known as nucleus
4. the proton mass is 1/1835 e mass