Atomic Spectra

Much of what we know about atomic structure comes from analysis of light either being emitted or absorbed by substances.

Elements can emit certain wavelengths (λ) when excited

Most sources of radiant energy (ex. light bulbs) produce many different wavelengths of light (continuous spectrum).

Elements produce certain colors when excited (via electrical discharge or heat).

H Ne

When separated by a prism, the light produced by each element produces a specific spectrum of light (atomic spectrum).

Spectral lines can determine the chemical composition of various materials or objects (ex. stars).

Spectral lines can also tell us about star movement!!!

Moving towards equipment

Moving away from equipment

What does the atomic spectrum of an element tell us?

Electrons (e-) are either emitting or absorbing energy by changing energy states.

n = 1

n = 2

n = 3

n = principal quantum #

# = Energy

- -

Energy level concept based on the Bohr Model of the atom.

Electron

Proton Neutron

- e- are found in orbits of certain radii.

- e- in a particular orbit has a specific energy and does not radiate energy while in orbit.

- Energy is emitted or absorbed when an e- changes from one energy level to another.

Types of electromagnetic (EM) radiation observed when e- change energy levels.