Pages 90-99

Electrons

• deBroglie—proved that particles with mass could have wave-like properties. A stream of e- could behave similar to a wave.

• He created the “wave-particle duality of nature” concept

Quantum mechanics

• Two types of movement:

• A) Newtonian Mechanics—describes behavior of objects big enough to see with unaided eye and traveling at ordinary speeds ( cars, planes, space shuttle)

Quantum mechanics

• B) Quantum Mechanics---describes behavior of objects too small to be seen with the unaided eye and traveling at a velocity near the speed of light (e-)

Electrons

• Heisenberg Uncertainty Principle—the position of an e- cannot be determined with certainty, because in order to “see” the e- one must strike it with a photon of light and this will change the momentum and the position.

Electrons

• Momentum---product of mass and velocity

Electrons

• Electron Cloud Model-(Quantum Model)– The nucleus is positive---due to p+

– The nucleus has neutral no

– The mass of atom is in nucleus– The volume around the positive center in which

the electrons are most likely located is referred to as the “e- cloud”

Electrons

• The e- cloud is the area of greatest probability in which the e- are most likely to be found at any given time.

•

Electrons

• Erwin Schrodinger-----derived an equation that treated the e- of H atom as a wave. He applied to all atoms.

Electrons

• Schrodinger’s quantum mechanical model of the atom describes each e- using 4 quantum numbers:

• “n” ---principal quantum number

• value of 1-7

• indicates the “size of e- cloud”

Electrons

• “l” ----sublevel of energy

• value of 0 to n-1

• indicates the “shape of the cloud”

• “m” ----describes cloud orientation in space

• “s” ---describes the spin of the e-

• values: clockwise spin +1/2

• counterclockwise spin –1/2

Electrons

• Greatest number of electrons in any energy level may be determined by :2n2

• Quantum level max e- number

• 1 2

• 2 8

• 3 18

• 4 32

Electrons

• Sublevels of energy:

• “s”---spherical shape only 2e-

• “ p” ----3 in number ( 2e- each)

• dumbbell in shape

• located on 3 axis

• “d” -----5 in number ( 2e- each)

• “ f” -----7 in number ( 2e- each )

•

Electrons

• Orbital ---space occupied by 2 e-

• Degenerate orbital---orbital with the same number of electrons and energy

• 3 p orbitals

• 5 d orbitals

• 7 f orbitals

Electrons

• Pauli Exclusion Principle---no two e- in an atom have the same set of 4 quantum #. E- in the same orbital must have opposite spins

• Hund’s Rule—no orbital can have 2e- until all orbitals have at least 1 e-

• Aufbau Principle---e- fill lower energy orbital first ( demo on board)

• Two exceptions to the filling rule:

• Cr----24

• Cu -----29

• Simplified notation or noble gas notation

• Use chart to find previous “noble gas” and work the e-configuration from there

• Demo

• Periodic chart divided into :

• Rows or periods-----( principal quantum #)

• Groups or families ( vertical columns)

• Group 1 alkali metalsGroup 2 alkaline earth metals

Group 17 halogens

Group 18 noble gas

Electrons

• Demo:

• e-configuration p 99

• orbital diagrams---

• noble gas notation

• arrow diagram---

Electron Dot Diagram

• Electrons in the outer most energy level are the e- most often involved in a chemical reaction.

• Valence e- ---- the e- in outer energy level

• Lewis Dot diagram:– Write the e-configuration for the element

– Write the chemical symbol

– Valence e- are placed in the 4 locations around the symbol –pairing them as necessary

Electron dot diagrams

• Write the Lewis dot diagram for:

• Carbon

• Chlorine

• Nickel

• Sodium

• Neon

• Calcium

Electron Dot Diagram

• Two exceptions to filling rule are:

• Copper

• Chromium

• Wave-particle duality of nature Probability

• Electron cloud quantum mechanics

• Heisenberg Uncertainty principle

• Lewis e- dot diagram

• Momentum

• Newtonian mechanics

• Orbital principal quantum number

• Pauli exclusion principle

• Sublevel

Work to do!!

• Page 126 # 12• Page 134 # 17• Page 141 #25,26,28• Page 145---vocab list• Page 146-149----#

38,39,44,46,49,52,53,55,59,61,64,78,79,80,81,82,84,86,87,91,93,101,102,103,104,

• Princeton review: 3,5,6,7,8,9,10