S.1.3.3 – S.1.3.5 Electron Configuration Flashcards
Electron properties
Both wave and particle
Schrodinger’s model
Mathematical equation that describes the probable location of the electrons in an atom (orbitals)
The location and trajectory of an electron are impossible to know
How many electrons can each orbital hold?
Two electrons
How can electrons be close together/in the same orbital?
Opposite spins counteract the repulsive charges of the electrons
How many sublevels and orbitals are there in each energy level?
- n = 1: 1s; 1 orbital
- n = 2: 2s, 2p; 4 orbitals
- n = 3: 3s, 3p, 3d; 9 orbitals
- n = 4: 4s, 4p, 4d, 4f; 16 orbitals
Energy level n has n sublevels, n² orbitals, and 2n² electrons maximum
Degenerate
Orbitals with equal energy being held away from the nucleus
2p orbitals have equal energy, but 2s has a different amount of energy
Aufbau Principle
Electrons are put into the orbital of the lowest energy first in an electron configuration of an atom in the ground state
Hund’s 3rd rule
Electrons in the same sublevel are put into separate orbitals
2px is populated, then 2py, then 2pz, then 2px
Electron configuration of ions
Sublevels s and p are on the valence shell (where electrons are typically gained and lost)
Metals lose s sublevel electrons first; transition metals also lose d sublevel electrons
Electron configuration
List all sublevels with superscript representing number of electrons in order of increasing energy
Condensed form
Write closest smaller noble gas and remaining sublevels with superscripts
Electron arrangement
Total number of electrons in each shell
Exceptions to electron configurations
- Chromium: 4s¹3d⁵ instead of 4s²3d⁴ because electrons do not like sharing orbitals + half-filled sublevel
- Copper: 4s¹3d¹⁰ instead of 4s²3d⁹ because of fully filled sublevel (small but enough change in potential energy for increased stability)
Pauli exclusion principle
Only two electrons can occupy the same atomic orbital and those electrons must have opposite spins
