Aufbau principle v2

Start: Memorizing numbers and letters only. No Shell/SubShell/Orbitals,

  1. Memorize the numbers (no shells/subshells/orbitals)
    344556
  2. Rearrange vertically
    3
    4
    45
    56
  3. Associate letters D and and FD
    3d
    4d
    4f5d
    5f6d
  4. Add +1 to right. And same to left
    43d4
    54d5
    64f5d6
    75f6d7
  • That pattern is the core Aufbau principle
    introduced as numbers and letters only (no shell/subshell/orbitals)

Next: Understanding of shells/subshells/orbitals.

Energy level = Shell.
Shell of SubShells.
SubShells of orbitals.
Orbitals of electrons.
Only 2 electrons per 1 orbital.
Electrons with opposite Spin (+ or -)

[Shell – SubShell – Orbital – 2electrons – +/-Spin]

Energy level # = SubShell count:

 1             1
 2             22
 3             333
 4             4444
 5             55555
 6             666666
 7             7777777
  1. All ELs 1 to 7 with Aufbau principle applied:
    1
    22
    33
    434
    545
    6456
    7567
  2. SubShells are designated as s,p,d,f,g,h,i
    1s
    2s2p
    3s3p3d
    4s4p4d4f
    5s5p5d5f5g
    6s6p6d6f6g6h
    7s7p7d7f7g7h7i

Putting it together following the Aufbau Principle:

  1. Aufbau with the letters:
    a) s and p as first and last!
    b) D and FD go in place as shown in (3) above!

1s
2s2p
3s3p
4s3d4p
5s4d5p
6s4f5d6p
7s5f6d7p

Orbitals, electrons, spin.

  1. Orbitals are inside the SubShells
    [Each SubShell adds 2 orbitals]
    s = 1 orbital
    p = 3 orbitals
    d = 5 orbitals
    f = 7 orbitals

Electron placement and count.

  1. Each orbital has 2 electrons. With opposite spin.
    [So if the SubShell adds 2 orbitals it adds +4 electrons]
    s = 1 orbital = 2 e-
    p = 3 orbitals = 6 e-
    d = 5 orbitals = 10 e-
    f = 7 orbitals = 14 e-