Nature of light and atomic spectrum
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Transcript of Nature of light and atomic spectrum
Nature of light and atomic spectrum
Energy from the sun Fusion – process of 2
nuclei that combine to make one (a new element ) and emitting large amounts of energy.
The sun is a giant ball of hydrogen gas undergoing a fusion reaction – releasing energy.
We know that energy as electromagnetic radiation
Electromagnetic Spectrum
Seeing color White light contains all
visible light spectrum R O Y G B V We see….
Black – absorbing all colors White – reflecting all colors Color – ex: red – reflecting
red and absorbing all other colors
White Light
Example – sun lightPasses through prism & separates into continuous spectrum.
Called continuous because all portions are visible – no blank areas
How is light formed?
All electrons in an atom exist naturally in their “ground state” e- configuration (all want to be close to nucleus – lower in energy)
If energy is added – electrons move to higher energy level – “excited state” – but don’t stay.
Electrons fall back to ground state and release light
How is light formed?An electron will jump to a higher
energy level by absorbing energy.
An electron will fall back to ground state by releasing light
http://www.colorado.edu/physics/2000/quantumzone/bohr.html
Atomic Emission SpectraElement’s atomic emission spectra is unique - used to determine an unknown compound.
Like a fingerprintAll elements have a different atomic emission spectrum
Found by using a spectroscope.
What is a spectroscope?Instrument designed to visually
observe spectra by splitting the LIGHT into its components.
Usually has PRISM or a DIFFRACTION GRATING to split light into components.
Diffraction gratings consist usually of thousands of narrow, closely spaced parallel slits (or grooves).
White light passed through a prism
One color of light passed through a prism
Continuous Spectrum
Emission Spectrum
Absorption Spectrum
continuous
emission
absorption
Hydrogen spectrum
Helium spectrum
The light of the gas is split into its components or an emission
spectrum