PRE-QUANTUM Flashcards
Our understanding of the electromagnetic structure of atoms has come from _________________________.
the analysis of the light emitted or absorbed by substances.
Electromagnetic radiation ______________ through space, it is also known as radiant energy.
carries energy
All types of electromagnetic radiation move through a vacuum at 3 x10^8 m/ which is _________________.
the speed of light
Waves are _________ which means that the pattern of peaks and troughs repeats itself at regular intervals.
periodic
The distance between 2 adjacent peaks.
Wavelength
the number of complete wavelengths or cycles that pass a given point each second.
frequency
the maximum height of the wave above the center line or the maximum depth below.
Amplitude
Wavelength and Frequency are __________________.
inversely proportional
It is a form of energy transmission in which electric and magnetic fields are propagated as waves through an empty space (vacuum) or through a medium.
electromagnetic radiation
It is a disturbance that transmits energy through space or a material medium.
wave
a display of various types of electromagnetic radiation arranged in order of increasing wavelength.
electromagnetic spectrum
it is produced when radiation from a polychromatic source is separated into its component wavelengths.
spectrum
Spectrum consist of a continuous range of colors.
Continuous
Radiation containing many different wavelengths.
polychromatic
Radiation containing a single wavelength.
monochromatic
spectrum containing radiation of only specific wavelengths.
line spectrum
The addition of waves (in phase)
constructive interference
the cancellation of the waves (out of phase)
destructive interference
The magnetic field component lies in a plane ________________ to the electric field component.
perpendicular
An electric field component is the region around an _________________.
electrically charged particles
a magnetic field is found in the region surrounding a _____________.
magnetic
________ ___________ Maxwell (1865)
James Clerk
It is the propagation of electric and magnetic fields.
electromagnetic radiation
It is produced by an accelerating electrically charged particle.
electromagnetic radiation
This explains many aspects of the behavior of light, several observations cannot be resolved by this model.
The wave model of light
What are the 3 observations?
The blackbody radiation, the photoelectric effect, and the emission spectra
What is a blackbody radiation?
the EMISSION OF LIGHT FROM HOT OBJECTS
define the photoelectric effect.
the EMISSION OF ELECTRONS FROM METAL SURFACES on which light shines.
What is the emission spectra?
the EMISSION OF LIGHT FROM ELECTRONICALLY EXCITED ATOMS
When ________ are heated, they emit _____________.
solids,
radiation
The wavelength distribution of radiation depends on ____________.
temperature
__________ proposed that _________ can either be released or absorbed by atoms only in discrete chunks of minimum size.
Max Planck,
energy
It means fixed amount
quantum
it is the smallest energy that can be emitted or absorbed as electromagnetic radiation
quantum
According to Planck’s theory, matter can emit and absorbed energy only in ____________ of multiples of hv.
whole number
Allowed energies are ___________ because the energy can be released only in ________ amounts.
quantized,
specific
Their values are _________ to certain quantities.
restricted
a minimum frequency of light
threshold frequency
defined as “tiny energy packets”
photons
light shining on a clean metal surface causes electrons to be ______________ from the surface.
emitted
Einstein assumed that the radiant energy striking the metal surface behaves like a ________ of tiny energy packets.
stream
the ______ of a photon is equal to the plankc’s contant times the frequency of the light.
energy
______ itself is quantized.
radiant energy
Under the right conditions, photons striking a metal surface can ________ their energy to electrons in the metal.
transfer
it is a certain amount of energy required for the electrons to overcome the attractive forces holding them in the metal
work function
What are the 3 series of spectral lines of atomic hydrogen?
Ultraviolet series (Balmer)
Visible series (Lynmann)
Infrared (Paschen)
What are the 3 series of spectral lines of atomic hydrogen?
Ultraviolet series (Balmer)
Visible series (Lynmann)
Infrared (Paschen)
The energy of light depends on its _______________.
frequency
X-rays can cause ________________.
tissue damage
Danish physicist who offered a theoretical explanation of the line spectra.
Niels Bohr
TRUE or FALSE
Not all radiation sources produce a continuous spectrum
TRUE
Recite the 3 Bohr postulates
- Only orbits of certain radii, corresponding to certain specific energies, are permitted for the electron in a hydrogen atom.
- An electron in a permitted orbit is in an “allowed” energy state. An electron in an allowed energy state does not radiate energy and, therefore, does not spiral into the nucleus.
- Energy is emitted or absorbed by the electron only as the electron changes from one allowed energy state to another. This energy is emitted or absorbed as a photon that has energy E = hv.
Explain the FIRST postulate of Bohr’s Model
Only certain special orbits called discrete orbits of electrons are allowed inside the atom.
Explain the SECOND postulate of Bohr’s Model
While revolving in these discrete orbits, the electrons do not radiate energy.
Energy levels indicate that _______________________.
each shell has got a defined energy level.
The ____________ of the orbit gets larger as _______ increases.
radius,
n (principal quantum number)
The lower (the more negative) the energy is, the more _______ the atom is.
stable
As n increases, the energy ________ and becomes less negative
increases
The lowest energy state is called the _____________
ground state
A higher energy state (n= 2 or higher) it is called ____________
excited state
If n= infinity, the energy is __________.
Zero
If n= infinity what happens to the electron?
The electron is completely separated from the nucleus due the increase in radius and the energy of attraction between the electron and nucleus approaches zero
It is the state in which the electron is completely separated from the nucleus is called ___________, or zero-energy, state of the hydrogen atom
reference
Explain the THIRD postulate of Bohr’s Model.
Electron can jump from one allowed orbit to another by either absorbing or emitting photons whose radiant energy corresponds exactly to the energy difference between the two orbits.
Electron jumps from a lower energy level to a higher energy level.
Absorption
Electron jumps from a higher energy level to a lower energy level.
Emission
Transition from one allowed state to another will involve a _____________.
photon
What did de Broglie proposed?
He proposed that the wavelength of the electron, or any other particle, depends on its mass, and velocity
the term matter waves is used to describe the ______________.
wave characteristics of material particles.
TRUE or FALSE
de Broglie’s hypothesis is true for all matter, any object of mass and velocity would give rise to a characteristic matter wave.
True?
It is a phenomenon in which X-ray passes through a crystal, an interference pattern results that is characteristic of the wave-like properties of electromagnetic radiation
X-ray diffraction
define X-ray diffraction
X-ray passes through a crystal, an interference pattern results that is characteristic of the wave-like properties of electromagnetic radiation
The German physicist Werner Heisenberg proposed that __________________ places a fundamental limitation on how precisely we can know both the ______________ of an object at a given instant
the dual nature of matter,
location and the momentum
The uncertainty principle states that ___________________.
this principle states that it is impossible for us to know simultaneously both the exact momentum of an electron and its exact location in space.
It is an equation that incorporates both the wave-like and particle-like behaviors of the electron.
Schrodinger’s wave equation
These are mathematical functions used to describe the electron in the atom
wave function
