Quantum numbers Flashcards
Louis de Broglie
1923- wave properties of matter
Since light waves have a particle behaviour (as shown by Einstein in the photoelectric effect), then particles (such as electrons) can have properties and characteristics of waves
Werner Heisenberg
1927 - the uncertainty principle
We can not know the position and momentum of a particle at a given time
Thus, electron behaviour (location and speed of electron) can never be known, but can only be described as a probability of finding an electron in a certain location
Erwin Schrodinger
1925- quantum (wave) mechanical model of the atom
developed wave mechanics to mathematically describe the electrons behaving like waves inside atom
What is an atomic orbital
A region in space in which there is high probability of finding an electron
Orbit vs. Orbital
Orbit
2-dimensional path
Fixed distance from nucleus
Circular path
2n^2 electrons per orbit
Orbital
3-dimensional region of space
Variable distance from nucleus
No path; shape of region varies
2 electrons per orbital
What do quantum numbers do and name them
Specify the properties of atomic orbitals and their electrons. Each electron in an atom can be described by FOUR quantum numbers:
1. principal quantum number
2. Orbital quantum number
3. Magnetic Quantum number
4. Spin Quantum number
what does the principal quantum represent
Indicates the main energy level or shell of an atomic orbital and its relative size. A higher n value indicates a higher level with a larger size and higher probability of finding an electron farther from the nucleus
What does the orbital quantum number represent
indicates the shapes of the orbital sublevels (l)
what does the third quantum number (magnetic) represent
indicates the orientation of the orbital in the space around the nucleus
What does the spin quantum number represent
indicates the spin of the electron (clockwise or counterclockwise)
An atom with one or more half filled orbitals (unpaired electrons) will be paramagnetic (show weak attractions to a magnet)
Pauli Exclusion Principle
no two electrons in an atom can have the same four quantum numbers (the last quantum number will be different, either +1/2 or -1/2)
Hund’s rule
every orbital in a subshell is singly occupied with one electron before any one orbital is doubly occupied, and all electrons in singly occupied orbitals have the same spin.
