Answer:
He developed the concept of concentric electron energy levels
Explanation:
Before Bohr's model, Rutherford's model was proposed. This model explains most of the properties of the atom but failed to explain the stability of the atom.
As per Rutherford's model, electrons revolve around the nucleus in the orbit.
But revolving electron in their orbit around nucleus would give up energy and so gradually move towards the nucleus and therefore, eventually collapse.
Bohr's proposed that the electrons around the nucleus move orbit of fixed energy called "stationary states". Electrons in these stationary states do not radiate energy.
Therefore, proposal of concentric electron energy levels refine the atomic models.
I believe the answer is B??????????? Hope this helps
~Queensupreme
If Robert has 4 grams of a substance and Jill has 10 grams of the same substance <span>Jill's sample will weigh more than Robert's sample.</span>
Sodium is very reactive but it’s a metal, and the problem asks specifically for a non-metal.
Silicone is technically reactive, but not super reactive.
Argon is a nonmetal, however it is an inert gas. It doesn’t react with anything.
We’re left with Chlorine, which is a non-metal in group 7, a highly reactive group, on the periodic table.
