How many time electron go around 1st bohr orbit of hydrogen in 1second?
Answers
Electrons do not orbit the nucleus in the way that planets orbit the Sun.
When a planet moves around the sun, you can plot a definite path for it that is called an orbit. A simple view of the atom looks similar and you may have pictured electrons as orbiting around the nucleus in the way of a planet. The truth is quite different.
A planet orbits because of gravity. An electron moves because of the electromagnetic force, which is a trillion trillion trillion (10^36) times stronger than the gravitational force.
To plot a path for something you need to know exactly where the object is and be able to work out exactly where it's going to be an instant later. You can't do this for electrons.
The Heisenberg Uncertainty Principle says - loosely - that you can't know with certainty both where an electron is and where it's going next. (What it actually says is that it is impossible to define with absolute precision, at the same time, both the position and the momentum of an electron.) That makes it impossible to plot an orbit for an electron around a nucleus.
Suppose you had a single hydrogen atom and at a particular instant plotted the position of the one electron. Soon afterwards, you do the same thing, and find that it is in a new position. You have no idea how it got from the first place to the second. You keep on doing this over and over and gradually build up a sort of 3D map of the places that the electron is likely to be found.
In the hydrogen case, most of the time the electron can be found anywhere within a spherical, easily defined region of space surrounding and quite close to the nucleus. Such a region of space is called an orbital. In a more complex atom some of its electrons inhabit strangely shaped orbitals.
What is the electron doing in the orbital? We don't know, we can't know. All you can say is that if an electron is in a particular orbital it will have a particular definable energy.