maximum number of electrons t the formula 2n2 is used to find the max. # of e- on any energy level....
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Maximum Number of Maximum Number of ElectronsElectrons
• the formula 2nthe formula 2n22 is used to find the max. # of e- on any energy level. is used to find the max. # of e- on any energy level.
- n = the energy level = (row on P.T.)- n = the energy level = (row on P.T.)
• Ex…Ex…
• energy level 3…energy level 3… 2(3)2(3)22 = = 18 e-18 e-
• energy level 6…energy level 6… 2(6)2(6)22 = = 72 e-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 NumbersQuantum Numbers
• there are four quantum numbers (actually letters)... there are four quantum numbers (actually letters)...
• the ‘address’ of an e-. the ‘address’ of an e-.
11stst = = nn = energy level of the e-. = energy level of the e-.
- 1 = lowest, 7 = highest - 1 = lowest, 7 = highest
22ndnd = = ll = shape of sub-orbital= shape of sub-orbital - 4 different shapes…found on each energy level- 4 different shapes…found on each energy level
- ‘the principle quantum number’- ‘the principle quantum number’
33rdrd = = mm = orientation of orbital in space. = orientation of orbital in space.
- which axis the orbital lies on - which axis the orbital lies on
44thth = = ss = spin of the e- on its axis. = spin of the e- on its axis.
- clockwise or counter-clockwise - clockwise or counter-clockwise
- represented by rows on the periodic table- represented by rows on the periodic table
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
22ndnd Quantum Number Quantum Number
• ll = shape of orbital= shape of orbital
• there are four orbital shapes, represented by letters…there are four orbital shapes, represented by letters…
• ss = sphere = sphere
- lowest energy- lowest energy
• each orbital can only hold each orbital can only hold 22 e-. e-.
= = 11 orbital orbital = = 22 total e- total e-
• pp = dumbbell = dumbbell = = 33 orbitals orbitals = = 66 total e- total e-
• dd = clover-leaf = clover-leaf = = 55 orbitals orbitals = = 1010 total e- total e-
• ff = double clover-leaf = double clover-leaf = = 77 orbitals orbitals = = 1414 total e- total e-
- highest energy- highest energy
2nd Quantum number cont.
• 2. Azmithual quantum number (l)- describes the subshell of the
orbital• l = n – 1• if l = 0 then the electron is in the s
subshell• l = 1 p subshell• l = 2 d subshell• l = 3 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 Orbitals
‘ ‘s’ orbitals’ orbital
‘ ‘p’ orbitalsp’ orbitals
Orbitals Orbitals ‘ ‘d’ orbitalsd’ orbitals ‘ ‘f’ orbitalsf’ orbitals
4th Quantum number
• 4. Spin (ms) – describes the electron’s intrinsic magnetism
• + ½ (spin up) or – ½ (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 last electron in P• The 5th electron in Na• The 9th electron in Cl• The 5th electron in O• The last electron in Cu• The last electron in Fe
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