How to use: 1. Tap energy levels to excite a hydrogen electron and watch it emit light. 2. Match line spectra to find the elements in an unknown. 3. Check yourself with 12 questions.
Hydrogen atom: tap a level
Transition–
Energy released–
Wavelength–
Region–
Hydrogen lines you have made (nm)
UV: 0IR: 0UV and IR photons are not visible, so they leave no line.
The rules
Ground state: the electron is in the lowest level it can be in.
Excitation: the electron absorbs energy (heat, electricity or light) and jumps to a higher level. This excited state is unstable.
De-excitation: the electron falls to a lower level and emits one photon. Photon energy = Ehigh − Elow.
Bigger drop → more energy → higher frequency → shorter wavelength (toward violet). A smaller drop gives a longer wavelength (toward red).
Dropping in steps emits one photon per step. 4 → 2 and then 2 → 1 gives two photons.
For these six levels: drops to n = 2 are visible, drops to n = 1 are ultraviolet, and drops to n = 3, 4 or 5 are infrared.
Only certain levels exist, so only certain colors are possible. That is why you get lines and not a rainbow.
Formulas: E = hfc = λfE = hc/λ
Which elements are in the unknown? Tick an element only if all of its lines are in the unknown. Tap or drag on any spectrum to move the guide line.
Unknown
The matching rule
An element is present only if all of its lines appear in the unknown.
One shared line is not enough. Sodium and neon both have a line at 616 nm.
Lines left over belong to another element.
Each element has its own set of energy levels, so its line spectrum is a fingerprint that no other element has.