L.3 Quantum Numbers Flashcards
Heisenberg’s Uncertainty Principle
The position and momentum of a particle cannot be accurately measured at the same time.
∆X x ∆P ≥ h/4𝝅
Hund’s Rule
No electron will “sit” next to each other if other orbitals are available.
Pauli Exclusion Principle
No two electrons will have the same quantum number, the last quantum number will have a + 1/2 or a - 1/2 spin.
Aufbau Principle
This is also known as the “building-up Principle” It states that electrons will fill from lower-to higher-energy subshells.
The n + l Rule can be used to help rank subshell by increasing order.
If two subshells posses the same n +l value, the subshells with the lower n value has a lower energy an will fill with electrons first.
The quantum mechanics model
Electrons do not travel in define orbits (Borh Model) but rather are localized in orbitals.
Difference between, shell, subshell, and orbital.
Location of s p d f blocks on Periodic Table
Principal quantum number
The average energy of a shell. Main energy level or shell.
n = 1, 2, 3, 4, 5
Angular Momentum Number or Azimuthal Number.
Describes the subshell within a given principal energy level.
(s, p, d, & f)
L= 0, 1, 2, 3
L = 0 to (n - 1)
Shape of orbital
s p d f
0 1 2 3
Magnetic Quantum Number
Specifies the particular orbital within a subshell where an electron is likely to be found.
ml = -L to + L
Orbital Orientation
Magnetic Spin Number
Magnetic Spin = ms
ms = +1/2 or -1/3
Electron Spin Direction
The process of atomic absorption and emission.
An electron can jump from a lower-energy to a higher-energy orbit by absorbing a photon of light of precisely the right frequency to match the energy difference between the orbits.
E =hf
When an electron falls from a high-energy to a low-energy level, a photon of light is emitted with an energy equal tot eh energy difference between the two orbits.
Infrared (IR) S p e c t r o s c o p y
&
UV-Vis Spectroscopy
Used to determine the structure of a molecule. The different bonds will absorb different wavelengths of light.
UV-Vis spectroscopy; looks at the absorption of light in the visible and ultraviolet range.
Fluorescence
When a fluorescent substance, such as a ruby, emerald or the phosphorus found in fluorescent lights is hit with ultraviolet radiation, it will begin to glow with visible light.
After an electron becomes excited by the light, it will return to a lower-energy orbital in tow or more steps, each step involves less and less energy, so at each step, a photon is emitted, if the wavelength emitted then might be in the visible range.
