Atomic Emission and Bohr Model

Limitations of Bohr model

• Works well for hydrogen, not multi-electron atoms

• Applies to all elements equally

• Explains electron spin

• Describes the behavior of protons

Bohr model vs. Rutherford model

• Electrons move in quantized orbits

• Electrons move in fixed paths

• Electrons are stationary

• Electrons move randomly

Spectral line

• line of color in emission or absorption spectrum

• a type of sound wave

• a measurement of light intensity

• a pattern of dark lines in a rainbow

Photon emission process

• absorbs energy, emits photon

• drops to lower energy, emits photon

• remains at the same energy level, emits photon

• gains energy, emits photon

Energy change equation in Bohr model

• @@rac{E_{final}}{E_{initial}}@@

• @@rac{E_{initial}}{E_{final}}@@

• @@ riangle E = E_{final} + E_{initial}@@

• @@ riangle E = E_{final} - E_{initial}@@

Energy quantization in Bohr model

• have only certain allowed energies

• can take any value

• is continuous

• depends on the mass of the electron

Identifying elements by spectra

• element has unique emission lines

• elements can be identified by their color

• elements emit light in all wavelengths

• elements have no specific spectral lines

Electron transition

• moves between energy levels in an atom

• is the process of electrons being emitted from an atom

• occurs only in ionic compounds

• is the movement of electrons in a conductor

Absorption vs. emission spectra

• Absorption: bright lines; Emission: dark lines

• Absorption: dark lines; Emission: bright lines

• Absorption: no lines; Emission: continuous spectrum

• Absorption: bright lines; Emission: continuous spectrum

Hydrogen emission spectrum

• of colored lines unique to hydrogen

• of a continuous spectrum

• of no visible lines

• of random colors