Exam 4 Flashcards
Excited atom makes what
Light emitted
Atom plus light absorption makes what
Excited atom
Distance between adjacent peaks on the wave (m)
Wavelength (λ)
Number of waves that pass a point per second (Hz or 1/s)
Frequency (v)
Vertical distance from the mid-line to the peak
Amplitude (intensity)
Speed of light (c)
3.00 * 10^8 m/s (in a vacuum)
Wavelength & frequency have what relationship
Inverse
Who developed a theory for light, proposing that light waves consists of 2 components; a vibrating electric field & a vibrating magnetic field
Maxwell
Who studied radiation emitted by matter & postulated that energy in matter is quantized
Max Planck
Smallest increment of energy that can be emitted or absorbed in the form of electromagnetic radiation
Quantum of energy
Energy equation of a single quantum
E=hv (E-energy J, v-frequency 1/2, h-Planck’s constant)
Plancks constant
6.6310^-34 Js
Light can cause electrons to be ejected from a metal surface
Photoelectric effect
If light has a frequency less than the threshold frequency, what happens
No electrons ejected
If light has a frequency greater than the threshold frequency, what happens
Number of electrons ejected is proportional to the light intensity
Who considered that light is composed of a stream of particles (photons- quantum packets of energy), extended Planck’s ideas
Albert Einstein
Electromagnetic radiation has what properties
Wave-like & particle-like properties
E=hv can also be written as
E=hc/λ
Short wavelengths have high energy and are
Damaging to life, like X rays
Long wavelengths have low energy and are
Safe, like radio waves
Atom that has the simplest atomic spectrum
Hydrogen atom
Each atom has its own unique
Atomic spectrum
Who studied the lines in the visible portion of the hydrogen spectrum (400-700nm)
JJ Balmer
Rydberg equation for calculating the emission lines in the hydrogen spectrum
1/λ=Rh[(1/n^2i) - (1/n^2f)]
Rydberg’s constant
109,678cm^-1
nf=1; ni=2,3,4… (ultraviolet)
Lyman series
nf=2; ni=3,4,5…(visible)
Balmer series
nf=3; ni=4,5,6…(infrared)
Paschen series
nf=4; ni=5,6,7… (infrared)
Brackett series
Danish physicist who developed a theoretical model for the hydrogen atom that restriceted on the sizes of the orbits & the energy that the electron can have in a given orbit
Niels Bohr
In Bohr’s model, lowest energy atoms are what
n=1, E<0
In Bohr’s model, highest energy atoms are what
n=∞, E=0
Electron in ground state absorbs energy & does what
Moves to a higher energy orbit, excited state