Question

Do the eletrons follow defined paths around the nucleus ? why?

Answer 1

Electron can be in any particular place in its electron cloud ( all possible points where an electron can be ). And we do not know where it is at any given moment. But according to Niels Bohr there are an orbits in which electron does not absorb and radiate energy, so it doesn't fall on nucleus. And it doesn't mean that electron is orbiting nucleus like macroscopic objects. It's motion has a quantum being. Which doesn't allows us to say that electron follows a defined path around nucleus.