what is an energy level
Lesson Summary. Energy levels inside an atom are the specific energies that electrons can have when occupying specific orbitals. Electrons can be excited to higher energy levels by absorbing energy from the surroundings. Light is emitted when an electron relaxes from a high energy state to a lower one.
Each energy level is labeled with the quantum number n (n=1, 2, 3,...) and the energy of a particular level can be determined by the following: En=-Rh (1/n^2). This is where Rh is the Rydberg constant of the element. For the simplest atom, the hydrogen atom, Rh=2.18*10^-18 J.