Orbitals, Electron Configurations
orbitals
- s orbital - lowest energy orbital, has spherical symmetry
- y2 approaches 0 as it gets farther apart from nucleus
- nodes - regions where y2 goes to 0
- orbital size increases as n increases
- p orbital - has dumbbell shaped orbital w/ 2 lobes
- shape shows average distribution of electrons, not its path
- every shell beyond the 1st has 3 p orbitals, each w/ different spatial orientation
- d orbital - occur beyond 1st 2 shells
- 5 different d orbitals
- f orbital - occur beyond 1st 3 shells
- 7 different f orbitals
- in atoms w/ multiple electrons, repulsions cause different subshells to be at different energies
- degenerate orbitals - orbitals w/ same energy
Pauli exlusion principle - no 2 electrons can have same set of quantum numbers (n, l, ml, ms)
- electron spin - property of electrons where each electron spins on an axis
- spin generates magnetic field
- ms = +1/2 or -1/2, spin magnetic quantum number
- each orbital can hold 2 electrons, as long as they spin in opposite directions
Hund's rule - in degenerate orbitals, lowest energy obtained if max # of electrons have same spin
- electrons w/ same spin magnetic quantum number have parallel spins
- electrons naturally repel one another, tend to occupy different orbitals if they can
electron configuration - way electrons are distributed among atoms' orbitals
- ground state - electrons in lowest possibly energy states
- orbitals filled in order of increasing energy (max 2 electrons per orbital)
- electrons w/ opposite spins are paired when in same orbital, unpaired electrons do not have an electron w/ opposite spin in same orbital
- condensed electron configuration - abbreviated electron configuration
- aka noble gas notation
- electron configuration of nearest noble gas w/ lower atomic number represented by chemical symbol in brackets
- only outer electrons matter in reactions
- core electrons - inner-shell electrons
- valence electrons - electrons given after noble gas core
- lanthanide (rare earth) elements - fill up the 4f orbitals
- actinide elements - fill up the 5f orbitals
- representative (main-group) elements - in s and p blocks of periodic table
- potassium (K) >> 1s22s22p63s23p64s1 or [Ar]4s1
- iron (Fe) >> 1s22s22p63s23p64s23d6 or [Ar]4s23d6
Subject:
Chemistry [1]
Subject X2:
Chemistry [1]