L.2 Exponential Decay & Atom Structure Flashcards
What is the equation for Plancks Relation.
- Frequency
- Wavelength
- E = hf
- E = hc/λ
E = Energy of a quantum
h = Plancks Constant = 6.625 X 10 -35 J/s
f = Frequency of the radiation
c = Speed of light = 2.88 X 10^8 m/s
The energy of each photon is proportional to the frequency of light.
Max Planck; energy emitted as electromagnetic radiation from matter comes in discrete bundles called quanta.
The energy of a quantum is given by this equation.
The equation for the Angular momentum of an electron. Bohr model
L = nh/2𝝅
The equation for the energy of an electron. Bohr model
E = - RH/n2
RH = Rydber Unit of energy = 2.18 X 10-18 J/e
The energy of the electron is proportional to the quantum number (n). As n increases the rest of the values increase from a negative side, and energy becomes less and less negative.
The equation for the energy of an electron in Transition (Bohr model).
E = -RH [(1/n2i) - (1/n2f)]
The energy of the emitted photon corresponds to the difference in energy between the high E initial and lower E final state.
+ E = Emission & -E = Absorption
Maximum number of electrons within a shell
2n2
Maximum number of electrons within a subshell
4L + 2
What are the four characteristics of an electron when it moves from a low level of energy to higher level energy?
- Absorbs light
- Higher Potential
- Excited
- Distant from nucleus
Explain the Bohr model.
In the Bohr model of the atom, a dense, positively charged nucleus is surrounded by electrons revolving around the nucleus in orbits with distinct energy levels. Each level has a discrete quantity of energy.
What is the photoelectric effect?
When a light of sufficiently high frequency (f), usually blue - uv is incident on a metal surface, metal atoms emit electrons.
Photon ——> metal surface ——> photoelectron emitted
What is the equation to used to find the maximum kinetic energy of an electron that was ejected from a metal surface by a photon?
What is the equation for Work Function?
Kmax = hf - w (from the photon that hit the metal surface and ejected the electron)
w = hft (of the metal which the ejected electron was emitted from)
ft= Frequency Threshold
h = Plancks constant
w= work function
What is the Equation for force?
mass X acceleration = Force
Electrons liberated from the metal by the photoelectric effect will produce a?
Net charge flow per unit time or CURRENT
What is Threshold Frequency?
The minimum frequency of light that causes ejection of an electron from a metal surface. (ft) This is an all or nothing response
What is the equation for Kinetic Energy?
KE = 1/2 mv2
What are the 3 different series for emission and absorption spectra for hydrogen?
- Lynman. n ≥ 2 to n = 1
- Balmer n ≥ 3 to n = 2
- Paschen. n ≥ 4 to n = 3
What is Mass Spectrometry?
In analytical chemistry, mass spectrometry is used to determine the molecular weight of some unknown molecule. Ions are accelerated through a closed magnetic field, inside a detector records the time it takes that ion to travel back to the initial starting point. Smaller ions/particles travel less and move faster, these are detected first.
F = ma
What is the equation for magnetic force in terms of magnetic field strength and velocity of an ion?
Fb = qV x B
Fb = Magnetic force
q = Charge of ion v = Velocity of ion goring through magnetic field
B = Magnetic field strenght
Coulombs Law
The force exerted by one charge q on another charge Q is given by
Coulomb’s law: Fe = K qQ / r2
Fe= Electric force
K = Coulomb’s Constant = 9 x 10^9 N
r = Distance between the two charges
PHYSICS FLOW CHART
Interpret a mass spectra graph
- X-axis
- Y-axis
- Parent Peak
- P+1 Peak
- Base Peak
