CBSE Class 11-science Answered
In a hydrogen atom, along with all other types of atoms, an electron can only orbit the nucleus in certain discrete orbits. These orbits correspond to electronic energy levels and are the only stable configurations in which electrons can ‘circle’ around the nucleus.
It turns out that the lowest-energy orbit for hydrogen is some distance away from the nucleus (on average). We can readily calculate this via the mathematics of quantum physics and, in particular, by solving the Schroedinger equation for the hydrogen atom.
The lowest energy level, or ground state, for hydrogen corresponds to the closest possible stable orbit to the nucleus. Given this, an electron in a hydrogen atom doesn’t spiral into the nucleus as there’s no closer state or orbit for it to move into. It’s as close as it possibly can get.