Physical and Inorganic Chemistry Flashcards
What is the photoelectric effect?
When ultraviolet with wavelengths from 2000 - 4000 A incident upon a metallic surface and electrons are emitted with some velocity.
What is the energy of the ejected photoelectron dependent on?
Dependent on the frequency of the incident radiation not upon it’s intensity.
What does higher intensity monochromatic light produce?
More photoelectrons all with the same energy.
What were the results of Rutherford and Gieger’s studies?
- The majority of alpha particles penetrate the gold foil undetected
- A few particles were scattered through a small angle
- A few suffered serious deflections as they passed through
- A few underwent direct backward scattering along the original pathway
What did Niels Bohr demonstrate?
Electrons are restricted to a specific set of energy levels - the energies are quantised.
What does wave-particle duality mean?
Electrons can behave as waves or particles but not at the same time.
What is the Heisenberg Uncertainty Principle?
“The more precisely the position is determined the less precisely the momentum is known.”
What does an electrons associated wavefunction describe?
The electron wave
How is the form of the wavefunction determined?
Using the Schrodinger equation.
What allows us to determine atomic orbitals?
Approximate solutions to the Schrodinger equation.
What do atomic orbitals tell us?
The probability of finding an electron at a particular point in an atom.
What does the principal quantum number, n, correspond to?
The gross orbital energy/ shell energy.
What does the orbital quantum number, l, correspond to?
The shape of the orbital (n-1).
What does the magnetic quantum number, ml, correspond to?
The orientation of the orbital. (-l through 0 to +l).
What are degenerate orbitals?
Those with the same energy.
What does the Aufbau Principle tell?
- Lowest energy orbitals fills first
- When filling degenerate orbitals no pairing occurs until each orbital contains one electron.
- Only two electrons can occupy an orbital
What are the valence electrons
?
Electrons in the shell with the highest value of n.
What does Lewis Structure show?
The nature of bonding in a molecule or ion.
What does VSEPR theory explain?
The vast majority of molecular geometries.
How are valence shell electron pairs arranged?
To minimise repulsions between themselves.
What is basic geometry controlled by?
The number of sigma bonding electron pairs.
What does the Born-Oppenheimer approximation suppose?
Nuclei move relatively slowly due to weight and so can be treated as being fixed at arbitrary locations.
How are bonding orbitals formed?
When atomic orbitals interfere constructively.
How are anti bonding orbitals formed?
when atomic orbitals interfere destructively.
