The number of rings in the Bohr model of any element is determined by what?
The Bohr Atom is a very simplified model of the electron positions of each element of the Periodic Table. Each Row of the periodic table is represented by an orbit.
Hydrogen and Helium are in the first energy level (row) of the periodic table and their Bohr Models would have one orbit.
The elements of the second energy level (row) Lithium through neon have two orbits in their Bohr Model. And like wise down the periodic table.
The diagram below is the Bohr Atom for Aluminum which is in the
third energy level and therefore the Bohr Model has three orbitals.
I hope this was helpful.