Quantum mechanics Flashcards
Define spectroscopy:
Study of the relationship between matter and electromagnetic interaction
Relationship between frequency and wavelength? Energy and frequency?
- Inversely proportional
- Proportional
From lowest energy to highest energy, segment the electromagnetic spectrum:
- Radio waves
- Microwave radiation
- Infrared radiation
- Visible light
- Ultraviolet radiation
- X-rays
- Gamma rays
As energy levels increase, the space between levels:
gets smaller, i.e. converges
Briefly describe the hydrogen emission spectrum:
Electrons falling from energy levels higher than n = 1 emit UV radiation, from higher to n = 2 emit visible light, from higher to n = 3 emit infrared radiation.
Energy level n = infinity means:
That the electron has been removed from attraction to the nucleus
Explain the emission line spectrum:
If electrons absorb energy, they move up energy levels (unstable relative to ground state) and emit equivalent energy to move back down. Corresponds to the wavelength of visible light released, which in turn shows the emission line spectrum.
Quantum number n represents:
The principal quantum number, i.e. the energy level
Quantum number l represents:
The secondary quantum number; angular momentum quantum number; i.e. the subshell divisions of n
Valid values of n?
1 -> infinity
Valid values of l:
0 -> (n-1)
Letter codes of l are? How many electrons in each?
- s, p, d, f, g…
- 2, 6, 10, 14, 18…
Quantum number m(l) represents:
The magnetic quantum number, i.e. the individual orbitals within the subshells
Valid values of m(l):
- l -> +l
Quantum number m(s) represents:
The spin quantum number, i.e. the direction in which an electron in an orbital spins
Valid values of m(s):
-1/2, 1/2
State the Aufbau principle.
Electron orbitals are filled up from lowest energy level up, i.e. building up.
State Hund’s rule.
In the case of degenerate orbitals (i.e. with the same energy level), each orbital is filled with a single electron before doubling up.
State the Pauli exclusion principle.
No two electrons may have the same quantum numbers; therefore each orbital may only have two electrons spinning oppositely
From left to right on the periodic table, with the lanthanides/actinides last, name the quantum “blocks” of the periodic table:
s -> d -> p -> f
Name four exceptions to the Aufbau principle and why they are exceptions:
- Copper
- Chromium
- Molybdenum
- Silver
Copper and silver move a 4s electron to the 3d orbital for a complete 3d shell. Chromium and molybdenum movie a 4s electron to the 3d orbital for a half-full 3d shell.
Why might an element be multivalent?
For the sake of stability - lose or gain electrons to become a noble gas, or get rid of s electrons (less stable)
Shape of an s orbital?
Spherical
Shape of a p orbital?
“peanut” shaped, along the x, y, and z axes respectively
What is the absorption spectrum? How does it compare to the emission spectrum?
The absorption spectrum is the energy absorbed by the electron when it gains energy. It will overlap perfectly with the emission spectrum.
