Chapter 21 Atomic Physics – Flashcards
Unlock all answers in this set
Unlock answersquestion
What is blackbody radiation?
answer
electromagnetic waves reflected off a blackbody
question
What is a blackbody?
answer
object that has absorbed almost all electromagnetic waves
question
What is an example of a blackbody?
answer
black hole
question
What is ultraviolet catastrophe?
answer
failed prediction of classical physics that the energy radiated by a blackbody at extremely short wavelengths is extremely large and that the total energy radiated is infinite; occurs in end of UV spectrum
question
Gamma rays act more like
answer
particles
question
Radio waves act more like
answer
transverse waves
question
What is Compton shift?
answer
increase in the wavelength of a photon emitted relative to the photon absorbed when scattered by individual electrons or nucleons
question
What is the photoelectric effect?
answer
emission of electrons from a material when light of certain frequencies shines on the surface of the material
question
What is a photon?
answer
unit or quantum of light; a particle of electromagnetic radiation that has zero rest mass and carries a quantum of energy
question
What is work function?
answer
minimum energy needed to remove an electron from a metal atom
question
What is the emission spectrum?
answer
increase in the wavelength of a photon emitted relative to the photon absorbed when scattered by individual electrons or nucleons
question
What is absorption spectrum?
answer
diagram or graph that indicates the wavelengths of radiant energy that a substance absorbs
question
What is the uncertainty principle?
answer
principle that states that determining both the position and the velocity of an electron or any other particle simultaneously is impossible
question
Red light has
answer
lower frequency, fatter wavelength
question
Violet light has
answer
higher frequency, shorter wavelength
question
What is the reasoning behind ultraviolet radiation?
answer
Max Planck said that this is because light is quantized
question
Higher temperature =
answer
higher energy EM wave emitted
question
What did ultraviolet catastrophe experiments show?
answer
Experiments showed that as the wavelength decreased, the energy decreased also
question
What is quantized energy?
answer
submicroscopic electric oscillators called resonators could only absorb and give off certain amounts of energy
question
What does quantized mean?
answer
bundles of energy (photons)
question
greater the frequency of light =
answer
greater the KE of the electrons ejected
question
higher frequency EM waves tend to act more like =
answer
particles
question
Louis deBroglie proposed that
answer
all matter, not just light, behaved as both waves and particles
question
Explain the Uncertainty Principle.
answer
to view an electron's location you would have to use light to see it. The light striking the electron would increase its energy, therefore changing its momentum
question
What is the electron cloud?
answer
area in which you can predict that you can there will be an electron in there
question
What does the fact that an emission spectrum contains only certain wavelengths show about electrons?
answer
Their energy is quantized
question
The principal quantum number represented by _____
answer
n
question
The spectrum of an incandescent solid is typically
answer
a continuous band of colors
question
What information can an emission spectrum reveal about the elements present in a sample?
answer
both their identities and relative concentrations
question
massive, positively charged particles that move at high speeds when emitted from radioactive materials
answer
alpha particles
question
the lowest energy state occupied by an electron
answer
ground state
question
the quantized features found inside an atom
answer
energy levels
question
the set of wavelengths absorbed by a gas
answer
absorption spectrum
question
the state of an atom that has absorbed energy
answer
excited state
question
Who discovered that electrons are quantized?
answer
Plank
question
Increasing intensity at threshold frequency
answer
EJECTS MORE ELECTRONS BUT DOES NOT INCREASE KE
question
If a photon ejects a blue light and a new, higher energy photon ejects a light ... what is the color? red? purple?
answer
purple bc less frequency, higher energy
question
What did Rutherford discover?
answer
the center of an atom's nucleus is positive
question
What do emission and absorption show and where does it occur?
answer
only in visible light? show colors reflected or absorbed with white light
question
What did Bohr discover?
answer
Hydrogen atom and that electrons have different energy levels
question
What did DeBroglie's wavelength show?
answer
all particles vibrate
question
Why can we not know the speed and location of an electron at the same time?
answer
time goes on and light makes the object move
question
What ideas led to the Electron Cloud?
answer
Bohr, deBroglie's wavelength, and Uncertainty Principle
question
What did Schrödinger say?
answer
we don't know what will happen until it happens, we also don't know the effects until they occur
