Electrons in Atoms13.3 Physics and the Quantum Mechanical Model13.1 Models of the Atom Atomic orbitals13.2 Electron Arrangement in Atoms

Physics in ChemistrySpeed of light, c = 3 x 108 m/sc = c = = wavelength (m)

“lambda” = = frequency (Hz) (Hertz = s-1)

◦ Also = frequency “nu” =

Electromagnetic spectrum p. 373

Atomic emission spectra = ◦Group of wavelengths of energy emitted by

electrons falling down to lower energy levels after being excited

◦Unique for each element◦Ground state vs. Excited state

E = h◦E = energy (J) (Joule)◦Planck’s constant, h = 6.626 x 10-34 Js◦ = frequency (Hz)

Photoelectric effect = ◦Metals eject electrons when light shines on

them◦Proves the particle concept of the dual

wave-particle behavior of light

Example: A popular radio station broadcasts with a frequency of 94.7 MHz. What is the wavelength of the broadcast?

= 94.7 MHz = 94.7 x 106 Hz = ?c = = c / = (3 x 108 m/s) / (94.7 x 106 Hz)

= ?

deBroglie’s equation = ◦Calculate the wavelength of a

moving particle, like an electron◦ = h / mv

= wavelength (m) h = Planck’s constant (Js) m = mass (g) v = velocity (m/s)

Heisenberg Uncertainty Principle = ◦You cannot know both the velocity

(speed) and position (location) of a particle at the same time