dec 31, 1884 - Niels Bohr
Description:
In 1913, Niels Bohr proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in certain well-defined quantities. Electrons should move around the nucleus but only in prescribed orbits. When jumping from one orbit to another with lower energy, a light quantum is emitted.Added to timeline:
Date:
dec 31, 1884
Now
~ 140 years ago