What is one indicator that electrons in atoms are limited to specific energy levels?

Answer 1

There is a lot of evidence that backs this up, and is the reason that scientists needed to invent quantum physics to describe small molecules.

Atomic spectroscopy is probably the most convincing. When we shoot energy at atoms, only certain very specific energies are released. In addition, molecules will only interact with very certain specific energies of electromagnetic radiation. These tow things lead us to believe that electrons only have specific levels of energy.

In addition, there is a minimum energy that electrons can take, called the Zero Point Energy, below which electrons cannot go. It makes sense that there would be this minimum energy. Since electrons have a charge, they radiate energy as they orbit the charged nucleus of the atom. Eventually, the electron should radiate so much that it looses all its energy and fall into the nucleus. This would make matter very unstable. But because electrons only take on certain values, this doesn't happen!

Answer 2

One indicator is that electrons in atoms can only occupy certain discrete energy levels, as seen in the discrete lines of an atomic emission spectrum where electrons emit photons of specific energies when transitioning between energy levels. This quantization of energy levels is a key feature of the quantum mechanical description of electrons in atoms.

Answer 3

One indicator that electrons in atoms are limited to specific energy levels is that when you excite atoms of different elements above their ground state, they emit different color lights,