Spectral Emission

Every element has its own characteristic spectral emission

Just as every fingerprint is unique, so is each spectral emission for each element on the periodic table

How and Why does an element give off color?

Each element has its own unique configuration

Changing Levels

Electrons have different energy levels, like floors in a building.

Lowest is called the Ground State.Higher states are Excited States.

Photons of light

…so they each emit (give off) different frequencies of light when electrons change from one energy level to another

Each element has its own unique configuration of light

These are the “fingerprints” of the atom

https://www.youtube.com/watch?v=-d23GS56HjQ

Flame tests and emission spectra both help us identify different elements

The light from hot gases and light sources can be analyzed with a spectroscope

The colors appear b/c of their different frequencies

This is called a line spectrum

The lines will always stay in the same position as the continuous spectrum of light

Actually…much of what scientists know about the structure of the atom is from the study of atomic spectra

The elements of the sun and galaxies was discovered from spectral lines

The element Helium was discovered on the sun (1868) first before it was discovered on Earth (1895)

Astronomers

Gases, stars, planets made up of MANY elements have spectra which include ALL of the component spectral lines.

It’s the scientist’s job to figure out which lines belong to which element.

This is how we find out what a star is composed of.

Napoleon Bonaparte-1821

After his death, scientists examined his hair with a spectroscope. Murder was initially suspected, b/c arsenic (40x normal), a poison, was found.

Although the initial diagnosis of death was perforated stomach ulcer, turned cancerous…the arsenic exacerbated his condition

Review

How are photons of light created?

What is given off (emitted) when an electron moves from a higher energy level to a lower one?

Which has a higher energy level, red or violet?

What does spectral emission tell us?

The elements found in stars and galaxies

That each element has its own unique fingerprint when producing light

Lab Activity

1) Flame test

2) Spectroscopes