hello everybody my name is Iman welcome back to my YouTube channel today we're continuing our high yield MCAT General chemistry videos we're on our fourth one and this one's about bora's model of the hydrogen atom part two now as a recap from part one we were talking about how in the early 20th century scientists were grappling with understanding why atoms emitted light in specific spectral lines now the bore model introduced the idea that an electron in a hydrogen atom could only have certain discrete energy levels these levels are quantized which means the electron can only exist in specific energy states and not in between them the lowest energy State or the ground state is where the electron is closest to the nucleus and higher energy states or excited States correspond to the electron being further away now the question we should pose is how do electrons transition from one state to another well the transition of an electron between these energy levels is going to involve the exchange of energy and this is specifically the exchange of energy in the form of photons or light particles now when an electron jumps from a higher energy level to a lower one it is going to emit a photon of Light which corresponds to the energy difference between these two levels this emission is observed as a line in the spectrum of light for example if we were OBS observing the hydrogen emission spectrum this is what it would look like and these lines correspond all right these lines correspond to the emission energy for the photon that has been emitted all right conversely when an electron absorbs a photon it gains energy and it's going to move from a lower energy level to a higher one here we can observe the hydrogen absorption Spectrum these are the frequencies of light that the hydrogen atom absorbs all right to move from a lower energy level to a higher one just like the hydrogen emission Spectra relates to frequencies of light that is emitted when an electron moves from a higher energy level to a lower one now the wavelength of the absorbed or emitted photon is precisely related to the energy change involved in the transition and we can Define that through this equation that we saw earlier energy equals Plank's constant multiplied by frequency of Light which is also equal to Plank's constant multiplied by the speed of light over wavelength all right now here you see again the absorption and emission spectrum of hydrogen the absorption and emission Spectra of hydrogen these provided empirical evidence that the energy states of electrons and atoms are quantized because not all frequencies of lights are being absorbed or emitted these spectral lines that you see here indicated that only photons with certain energies were emitted or absorbed by hydrogen atoms according to classical physics if the energy levels were continuous you would expect a continuous spectrum of colors as electrons could absorb or emit any amount of energy but these discrete lines that you see in the hydrogen absorption and emission spectas suggest that electrons can only transition between fixed energy levels and so abs absorbing or emitting photons with energies only happened when they were equal to the distance and the differences between those levels all right with that being said we're going to end part two here and we will continue with more information in part three so please stay tuned let me know if you have any questions comments concerns down below other than that good luck happy studying and have a beautiful beautiful day future doctors