# Maximum Number of Electrons the formula 2n2 is Maximum Number of Electrons the formula 2n2 is used to find the max. # of e- on any energy level. - n = the energy level = (row on P.T.) Ex energy level 3 2(3)2 = 18 e energy level 6 2(6)2 = 72 e- Quantum numbers Principal Quantum Numbers

Map to determine location of the electrons.. (Methods for denoting e- arrangement for an atom: orbital notation) Quantum Numbers the address of an e-. there are four quantum numbers (actually letters)... 1st = n = energy level of the e-.

- the principle quantum number - represented by rows on the periodic table - 1 = lowest, 7 = highest 2nd = l = shape of sub-orbital - 4 different shapesfound on each energy level 3rd = m = orientation of orbital in space. - which axis the orbital lies on 4th = s = spin of the e- on its axis. - clockwise or counter-clockwise

1st Quantum Number 1. Principal Quantum Number (n) Describes the size and energy of an orbital n E Distance from nucleus & stability Ex. n=1

2nd Quantum Number l = shape of orbital there are four orbital shapes, represented by letters each orbital can only hold 2 e-. s = sphere = 1 orbital = 2 total e- lowest energy p = dumbbell = 3 orbitals = 6 total e d = clover-leaf = 5 orbitals = 10 total e f = double clover-leaf = 7 orbitals = 14 total e- highest energy 2nd Quantum number cont.

2. Azmithual quantum number (l)describes the subshell of the orbital l=n1 if l = 0 then the electron is in the s subshell

l=1 l=2 l=3 p subshell d subshell f subshell 3rd Quantum number

3. Magnetic (ml) describes the 3 dimensional orientation of an orbital Values of ml = -l to +l Ex. if l = 0 then ml = just one orbital If l = 1 then ml = 3 orbitals (-1, 0, 1 = x, y, z) Orbitals

s orbital p orbitals Orbitals d orbitals f orbitals 4th Quantum number

4. Spin (ms) describes the electrons intrinsic magnetism + (spin up) or (spin down) each e- occupies the lowest energy orbital available SPDF blocks in periodic table

Quantum Numbers Practice What are the 4 quantum numbers of: The The The The The The

last electron in P 5th electron in Na 9th electron in Cl 5th electron in O last electron in Cu last electron in Fe