Quantum Theory, Quantum Mechanics Flashcards
This theory states that that atoms or molecules emit energy in certain discrete quantities called “quanta or quantum.”
Quantum theory
Who proposed the quantum theory?
Max Planck
What is the equation for energy E of a single quantum of energy?
E = hv where (h) is called Planck’s constant and (v) is the frequency of radiation
A vibrating substance by which energy is transmitted
Wave
The distance between identical points on successive waves
Wavelength (λ ; lambda)
Number of waves that pass through a particular point in 1 s.
Frequency (ν ; nu)
Vertical distance from the midline of a wave to the peak or trough
Amplitude
The point at which the amplitude is zero
Node
It is defined as the product of wavelength and frequency (λν)
speed (u)
Defined as a wave with an electric and magnetic field components
Electromagnetic waves
Emission and transmission of energy in the form of electromagnetic waves
Electromagnetic radiation
What is the speed of electromagnetic waves (aka light)?
c = 2.99792458 × 10^8 / 3.0 x 10^8 m/s
Shortest waves with the highest frequency
Gamma rays
An interference that occurs when two waves are in phase/identical, resulting in a pattern made from the addition of the two waves
Constructive interference
An interference that occurs when two waves are out of phase, resulting in the perfect cancellation of the two waves
Destructive interference
Smallest quantity of energy that can be emitted or absorbed in the form of electromagnetic radiation
Quantum
What is the value of Planck’s constant?
6.63 × 10^−34 J
A phenomenon in which electrons are ejected from the surface of certain metals exposed to light of at least a certain minimum frequency
Photoelectric effect
Below the threshold frequency no electrons were ejected no matter how intense the light
TRUE
The number of electrons
ejected was proportional to the intensity (or brightness) of the light, but the energies of the
ejected electrons were not.
TRUE
It is the particle of light, with an energy E using the same form as Planck’s equation
Photons
The energy that binds the electrons in the metal
Work function Φ
In the photoelectric effect, no electrons are ejected when the frequency of light is below the threshold frequency of a metal. When the frequency of light is above the threshold frequency, electrons are ejected with kinetic energy that increases with increasing frequency of light.
TRUE
It is the state where an atom absorbs energy and its electrons form an orbit to another with a higher energy
Excited
The state after an electron falls to an orbit of low energy / lowest energy state of a system
Ground state
The more intense the light, the greater the
number of electrons emitted by the target metal; the higher the frequency of the light, the greater the kinetic energy of the ejected electrons
TRUE
What is represented by the value 2.18 x 10^-18 J
Rydberg constant for the hydrogen atom
How does Bohr’s model of the atom explain the line spectrum of hydrogen?
Bohr tells us that the electrons in the Hydrogen atom can only occupy discrete orbits around the nucleus (not at any distance from it but at certain specific, quantized, positions or radial distances each one corresponding to an energetic state of your H atom) where they do not radiate energy.
When the electron moves from one allowed orbit to another it emits or absorbs photons of energy matching exactly the separation between the energies of the given orbits (emission/absorption spectrum).
The difference between the energies of the initial and final states is denoted by?
ΔE = Ef− Ei
What is meant by the dual nature of an electron?
It can be considered both as a wave and as a particle
It states that it is impossible to know simultaneously both the momentum and position of a particle with certainty
Heisenberg Uncertainty Principle
How does the Heisenberg principle contradict Bohr’s atomic model?
