Download Chapter 5 PPT/Notes A

CHAPTER 5:Electrons in Atoms
Light and Quantized Energy
The Wave Nature of Light
•Light is a type of electromagnetic radiation.
•Light is a particle that travels as a wave.
•See p 137 for parts of a wave.
The Wave Nature Of light
• Electromagnetic
radiation
Parts of a Wave
• Wavelength is the length of a wave from
one location to the same location in the
next wave…crest to crest for example.
• Amplitude is the vertical distance from
origin to crest or origin to trough.
• The trough is the ‘bottom-point’ of a wave
and the crest is the ‘peak’ of a wave.
• Frequency is how many waves per unit of
time pass a point.
• Period is how long it takes for a
wavelength to pass a point.
• F=1/period
Wavelength and Frequency
• c=f•λ
• where c=3.00x108 m/s λ=wavelength
and f =frequency.
The Electromagnetic Spectrum
• Electromagnetic Spectrum
Wavelength,Energy, and
Frequency
• Wavelength and frequency are inversely
related…like on a see-saw.
• Ef
λ
The Particle Nature of Light
• A quantum is the amount of energy
required to move an electron from one
energy level to the next.
• E=hf
• …where E=energy and h=Planck’s
constant h=6.626x10-34Js
• This calculates the energy of a photon or
quantum.
Atomic Emission Spectra
Absorption and Emission Spectra
• Absorption spectra …Emission Spectra
5.2 Quantum Theory and the Atom
• Bohr’s model of the
atom…