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Electrons
• Negative charge e-
• Located in the electron cloud far from the nucleus
• Have mass, but it is negligible
• Also have wave-like properties
Bohr Model of the atom
• Bohr model: e- move in fixed orbits around the nucleus
Wave-Mechanical Model of the atom
• Wave-mechanical model: e- move in areas called orbitals
• An orbital is a region where an e- is likely to be found
Electrons have
ElectronS in their lowest possible energy state are in the
GROUND STATE
ElectronS in a HIGHER possible energy state are in the
EXCITED STATE
Ground State
Excited State
e-
For an e- to jump from the ground state to the excited state, it must absorb energy (a photon of light)
When an e- falls back down from excited state to ground state,it releases energy (a photon of light)
Fluorescent and neon lights arecaused by excited e- returning
to ground state
Ordinary light is seen by our eyes as a continuous spectrum
The visible light produced by e- falling back to ground state is called a bright line spectrum
Light is emitted only at certain wavelengths
Each element has its own distinct bright line spectrum
Bright line spectra can be used to identify elements,by comparing the spectral lines to known spectra
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