Quantum Numbers and Electron Configurations

a region of probability where an electron can be found.

s

d

p

f

Remember these are NOT electrons, they're just regions of space where an electron can be found.(Each can hold up to 2 electrons)

n=Principle Quantum Number

n=1

n=2

n=3

n=4

Determines the shape of an orbital

Each value of l

l indicates a specific s, p, d, f subshell (each unique in shape.

he value of l

l is dependent on the principal quantum number n

n.

l=0,1,2,3,4...,(n-1)

Determines the number of orbitals and their orientation within a subshell

s=1

d=3

p=5

f=7

designates the direction of the electron spin and may have a spin of +1/2, represented by↑, or –1/2, represented by ↓

No two electrons in the same atom can have identical values for all four of their quantum numbers.

In other words:

(1) no more than two electrons can occupy the same orbital

(2) two electrons in the same orbital must have opposite spins 

states that electrons fill lower-energy atomic orbitals before filling higher-energy ones (Aufbau is German for "building-up")

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.

the more visual way to represent the arrangement of all the electrons in a particular atom

Each sublevel is labeled by its principal energy level and sublevel

Electrons are indicated by arrows inside the circles. An arrow pointing upwards indicates one spin direction, while a downward pointing arrow indicates the other direction.

Electron configuration notation eliminates the boxes and arrows of orbital filling diagrams.