ATOMIC EMISSION SPECTRA

Specific wavelengths and frequencies of light produced by energized atoms

How do atoms make light?

Atoms absorb energy (flame, electricity, fusion)

Electrons jump up to a higher shell, excited state

Electrons fall back to original shell or ground state

Energy is given off in the form of lightEnergy in

Electrons move shells

Electrons in normal location; stable and low energy

Electrons in a higher energy shell; unstable

Ground State Excited State

Emission Spectra AnimationBozeman Science

Bigger jumps = more energy

Atomic emission spectra for Hydrogen Each line is made by a specific electron making a specific energy jump. Hydrogen’s 1e makes multiple jumps

High energy

Low energy

How many e- jumps? What distances?

Hydrogen gas energized with electricity

Blue light is separated into colored lines of different wavelengths

Each atom makes a unique atomic emission spectra due to it’s unique number of electrons

Low energyHigh energy

Can be used likeAtomic Fingerprints

Each atom has a different # of electrons and thus a unique spectra. Thus they can be matched to identify the elements in stars

Analysis of that light tells us star’s elements, temperature, age, energy,, direction of motion, speed, distance, type of star….

Nitrogen-7 electrons

Hydrogen-1 electron

Helium-2 electrons

Nitrogen- 7 electrons

Neon-10electrons

Mercury-80 electrons

How do we see the lines?Refraction!

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)

Animate it!

αβ0

Β-1β1

d

Diffracted light

Reflected lightGrating normal

+ -

Incident light

Diffracted light

A Diffraction grating-uses reflection to the same result