Answer to Question #197579 in Quantum Mechanics for Fatin

Question

What is the relation between the size of a Bohr atom and the size of a Schroedinger atom?

Answer 1

Here, we need to define what is the size. In case of Bohr atom, this seems to be simple. Radius of atom is the radius of an electron orbit. Electron is a particle, its orbit is stable and can be described as a circle with radius $r_n =a_B n^2$.

For Schroedinger atom, there is no localized electron. Electron can be anywhere. So if the size is possible location of the election, then Schroedinger atom has infinite size. However, the most probable location of electrons in Schroedinger atom is Bohr orbits. So if the size is limited by the most probable location, then they have equal size. Most physicists accept the last definition of Schroedinger atom. Therefore, in this conception of size, they have equal size.

Answer: They are equal.