QUANTUM MECHANICAL MODEL

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Determines the allowed energies an electron can have

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Determines how likely it is to find the electron in various locations

QUANTUM MECHANICAL MODEL 

CLOUD or ORBITAL MODEL

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PROPABILITY OF FINDING AN ELECTRON WITHIN A CERTAIN VOLUME OF SPACE AROUND THE NUCLEUS (orbital)

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High density =high propability Low density =low probability Shape of the cloud represents a 90% probability

QUANTUM MECHANICAL MODEL

GENERAL PLAN 

PRINCIPLE ENERGY LEVEL (n)

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ENERGY SUBLEVELS (l) indicate the shape of orbital which contains

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ATOMIC ORBITALS (m) Orientation of orbital around nucleus (Electrons found here)

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Number of electrons per atomic orbital =2

QUANTUM MECHANICAL MODEL principle energy levels 

PRINCIPLE ENERGY LEVELS

 LABELED BY PRINCIPLE QUANTUM NUMBERS (n) n=1,2,3,4,5,6,etc.

   As n> the electrons energy > and distance from nucleus > Can be called a shell Within a given energy level there may be several sublevels that have orbitals

QUANTUM MECHANICAL MODEL energy sublevels 

ENERGY SUBLEVEL (l)

 Each energy sublevel corresponds to orbitals of different shapes where the electron is likely to be found  Sublevel could be called a subshell

QUANTUM MECHANICAL MODEL energy sublevels 

ENERGY SUBLEVEL (l) (Orbital shapes)

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Labeled by letters

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s = spherical shape p = dumbbell shape d = clover leaf +

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f = too complicated

QUANTUM MECHANICAL MODEL atomic orbitals 

ATOMIC ORBITAL (m)

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(Orbital orientation)

THE s SUBLEVEL HAS ONLY ONE ORBITAL, s

QUANTUM MECHANICAL MODEL atomic orbitals 

Atomic orbital orientation)

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(orbital

THE p SUBLEVEL HAS THREE ORBITALS—p x , p y , p z

QUANTUM MECHANICAL MODEL atomic orbitals 

Atomic orbital (orbital orientation)

 THE d SUBLEVEL HAS 5 ORBITALS– d xy , d xz , d yz , d x2-y2 ,d z2

QUANTUM MECHANICAL MODEL atomic orbitals 

Atomic orbital(orbital orientation)

 THE f SUBLEVEL HAS 7 ORBITALS  They are too complicated to show or name

QUANTUM MECHANICAL MODEL electron location  Within each orbital there can be a maximum of 2 electrons  EACH ELECTRON MUST HAVE AN OPPOSITE SPIN +1/2 or -1/2

QUANTUM MECHANICAL MODEL RELATIONSHIPS  Relationships between     Energy levels n=energy level SUBLEVELS n=number OF SUBLEVELS ORBITALS n 2 =number OF ORBITALS PER ENERGY LEVEL ELECTRONS 2n ENERGY LEVEL 2 = MAXIMUM NUMBER OF ELECTRONS PER

QUANTUM MECHANICAL MODEL SUMMARY Organization Designation Principle energy level (shell) Sublevel (subshell) Atomic orbital Spin

Energy Level Subshells or sublevel # of Orbitals Maximum number of e s per orbital Total number of e s per energy level

n = 1 n = 2 n = 3 n = 4

QUANTUM MECHANICAL MODEL 

Electron configuration

 The relationship between energy and stability   Electrons and nucleus interact to make the most stable arrangment possible (lowest energy) There are three rules for electron configurations

QUANTUM MECHANICAL MODEL 

Electron configuration

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Aufbau princple

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Electrons occupy the orbitals of lowest energy first

QUANTUM MECHANICAL MODEL  AUFBAU RULE

QUANTUM MECHANICAL MODEL  AUFBAU ORDER FILLING

QUANTUM MECHANICAL MODEL 

Electron configuration

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Pauli exclusion principle One orbital may describe at most 2 electrons To occupy the same orbital, the two electrons must have opposite spins

↑↓

QUANTUM MECHANICAL MODEL 

Electron configuration

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Hunds rule When filling orbitals of equal energy, one electron occupies each orbital until all orbitals contain one electron with the same spin direction

QUANTUM MECHANICAL MODEL 

Electron arrangement

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Orbital notation Electron configuration notation Exceptions Half-filled sublevels are less stable than filled sublevels but more stable than other configurations