Atomic Emission Spectra

1. Atomic Emission Spectra Specific wavelengths and frequencies of light produced by energized atoms

2. Electrons move shells Ground State Excited State • Electrons in normal location; stable and low energy • Absorb energy and jump UP to… • Electrons in an elevated energy shell; unstable & higher energy • Fall back and release energy as light! Emission Spectra Animation

3. High energy Bigger jumps = more energy Low energy Atomic emission spectra for Hydrogen. 1 electron makes different jumps; each releasing a single color line of energy dependent on the jump distance

4. Can be used likeAtomic Fingerprints Each atom has its own # of electrons! Each atom makes it’s own color flame which can be separated into it’s own emission spectra. Star’s make spectral lines based on their atomic composition

5. How do we see the lines?Refraction! Grating normal • Is the bending of light by being slowed down • Shorter waves (blue) are bent more than longer waves (red) • The result is separation of color (a rainbow) Incident light Reflected light + - Diffracted light β0 α Diffracted light Β-1 β1 Animate it! d A Diffraction grating-uses reflection to the same result

7. Atomic Spectra-specific wavelengths of light produced by energized atoms Each atom produces a distinct atomic spectra (fingerprint) due unique structure Line spectra; energized electrons http://ircamera.as.arizona.edu/NatSci102/NatSci102/lectures/spectroscopy.htm http://www.youtube.com/watch?v=8TJ2GlWSPxI&feature=related

8. How do stars make light?---Fusion under gravity Analysis of that light---tells us temperature, atomic composition, age, energy, distance…. Atomic Emission Spectra-atoms produce specific wavelengths of light as their electrons are energized Na He High energy Low energy Each line in the spectra is caused by a specific electron being energized a specific amount Act like fingerprints-as each atom has a specific electron configuration