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September 26, 2006 at 12:45 am #714
:describe how bohr used emission to explain the existence of energy levels in atoms
September 26, 2006 at 12:45 am #14319
describe how bohr used emission to explain the existence of energy levels in atoms
September 28, 2006 at 5:31 pm #14320Anonymous
The Bohr structure of an atom refers to the ideas that Bohr put forward in 1913, electrons rotating around the nucleus in allowed orbits or shells. While the Bohr structure of atoms is unlikely to be asked at Leaving Certificate level, a knowledge of it is essential to the understanding of many of the other topics on the course.
Bohr and the Hydrogen Spectrum
Bohr's theory, which resulted from his explaining the line spectrum of hydrogen, is that electrons can only revolve around atoms in certain allowed orbits or energy levels. When energy is given to an atom, electrons can move to higher energy levels, and when they return to their lower levels, energy is given out in the form of radiation – light, ultraviolet or infrared. This is the origin of the various lines in the spectra of the different elements.
October 7, 2008 at 2:51 am #14321
Bohr used the model of elecrtons revolving in shells around the nucleus.
He realised that when the electrons were in the shells they had a fixed amount of energy .The shells became known as energy levels.
Therefore for an electron to be positioned in an energy level it had to have a fixed amount of energy.
But if energy is passed through an atom (heat for example) the electron will gain that energy. It now has more energy so cannot stay in the energy level it was originally in (its ground state)
It will move up to a higher energy level because of the extra energy it has. It is very unstable in this energy level and is said to be in an excited state.
Because it is unstable in this energy level it will eventually fall back down to the original energy level.
It will give out energy as it falls back down. This energy will be represented by lines of a particular frequency in an emmission spectrum and this is evidence for the existence of energy levels!!!
If you were asked why do all elements have specific/unique emission spectrums your answer would be that the electrons in every atom are arranged differently so therefore there would be different electron transitions ~(that is electrons would move up to and fall down from differnt energy levels) These different electron transitions give rise to different lines in the emmission spectrum and therefore a unique one for each element.
If there is any of this you dont understand mail me.
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