niels bohr (1913) bright-line spectrum –tried to explain presence of specific colors in...
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Niels Bohr (1913)
• Bright-Line Spectrum– tried to explain presence
of specific colors in hydrogen’s spectrum
• Energy Levels– electrons can only exist in
specific energy states
• Planetary Model
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Orbits or Energy levels
• Area where e-
are trapped within an atom
• Atoms have multiple orbits
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Electrons Produce Light!!
• Electrons (e-) move within atoms– (e-) movement is caused by
energy– (e-) move in different orbits
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Photons
• A particle form of light or electromagnetic radiation
A photon walks into a hotel and checks in. "Do you want a hand with your luggage?" asks the receptionist. "No thanks", replies the photon, " I’m travelling light".
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Excited state
1. Electrons jump to a higher orbit
2. Caused by atoms absorbing energy
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Ground state
• Electron falls back to lower level (ground state)
• Energy is released as electromagnetic radiation (E.R) (photon)
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Transition of n 3→2 4→2 5→2 6→2 7-2
Wavelength (nm) 650 500 450 425 400
color red blue green violet UV
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Quantum or jump
• when an e_ jumps orbits it transports to the next orbit!!!
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A photon can be released as any electromagnetic energy
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Spectral lines summed up
1. e- are in fixed orbits
2. e- can get excited, and jump to a higher orbit, if they absorb the appropriate energy
3. e- will fall back to lower level (ground state) and release a photon of similar energy (visible light)
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5 points of the Bohrs Model
– 1. elements produce spectral lines also known as energy levels
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2. Energy levels are represented by letters
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– 3. Energy levels get larger the farther away they are from the nucleus
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–4. larger the energy level more electrons they can hold
–5 Each energy level can only hold so many electrons
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Problems?
• Why do electrons they stay in their orbits?