DO NOW: Put these in order of lowest energy to highest energy Yellow light, ultraviolet light, infrared light, microwaves (Hint; wavelength is usually given in nano-meters)

Qwiz Time Dawgs Put your stuff away EXCEPT for Calculator Reference Tables Something to write with

5.3 Quantum model

UpDaTiNg ThE BoHR MoDeL: QuAnTuM oR WaVe MeChAnIcaL MoDeL

UpDaTiNg ThE BoHR MoDeL: The Bohr Model was very good at explaining many things about atoms and electrons and how they behaved. Just like your wardrobe needs updating, so did the model of the atom. A revolution in physics occurred in the early 1900’s when experiments showed that matter, just like light energy, could have a dual nature…it can act as a particle or a wave.

The Wave Mechanical Model Still has a dense positive nucleus where protons and neutrons are located Using complicated math, this math showed that electrons were not moving in definite fixed orbits like planets but had distinct amounts of energy.

Four “Quantum Numbers” Four “Quantum Numbers” are used to describe the location of the electron. Principle Energy Levels (PEL) get divided into sublevels. (PEL are also called the PRINCIPLE QUANTUM NUMBER. ) These sublevels are designated: s, p ,d and f The number of sublevels is determined by the number of the principle energy level (n): n = # sublevels

Sidebar: Memory Hook for #orbitals in each sublevel

Sidebar: Memory Hook Each box = orbital (can fit 2 e- each) 4 p 3 2 1 Orbitals s PEL

s  p  d  f Within the same principle energy level: the sublevels have different energies: s  p  d  f lowest  highest energy energy

s p d f The sublevels are divided into orbitals (rooms) where electrons are found. Each orbital can hold 2 electrons. Orbitals are “regions” or “areas” around the nucleus

The number of orbitals depends on the sublevel type: x 2 = # of electrons in sublevel s p d f 1 2 3 6 5 10 7 14

orbital An orbital is defined as a region in which an electron with a particular amount of energy is most likely to be found. The probability of finding an electron near the nucleus is ________ The probability of finding an electron far away from the nucleus is __________

New model shows the probability of finding the electron

1 S orbital = 1S sublevel S sublevel gets larger as n

3 P orbitals = P sublevel

This volume outside the nucleus are often described as an Electron Cloud.

So far we have 3 Quantum “Numbers” 1) Principle Energy Level: “n” which are divided into… 2) Sublevels: s, p d, f which are divided into… 3) Orbitals: s has 1, p has 3, d has 5, f has 7…

The 4th Quantum #: Spin Within an orbital, the two electrons spin in opposite directions to overcome the repulsion they feel for each other (like charges repel.)  

The electrons in an orbital spin in opposite directions!

Wave Mechanical Model showing orbitals together

Principle Energy Level A graphic to help…. Principle Energy Level Sublevels Sublevels Sublevels Orbital Orbital Orbital Orbital O O O O Spin (up) Spin (down) U D u d u d u d u d u d u d u d

The 4 “Quantum #s Give the Address of the Electron Street House Room Position in room Principle Energy Level (n = #) Sublevel (s,p,d,f) Orbital (box in box-diagram Spin (up or down)

Sublevels & Orbitals in PEL Principle Energy Level Sublevel (s) Present Orbitals Present Total # of e per PEL 1 2 s 1 2 s 1 8 p 3

Sublevels & Orbitals in PEL Principle Energy Level Sublevel (s) Present Orbitals Present Total # of e per PEL 3 s 1 p 3 18 d 5

Sublevels & Orbitals in PEL Principle Energy Level Sublevel (s) Present Orbitals Present Total # of e per PEL 4 s 1 p 3 32 d 5 f 7

What “n” can tell you! n = Number of principle energy levels n = number of sublevels (s,p,d,f) n2 = number of orbitals in that PEL 2 n2 = Total number of electrons in that energy level

Quantum Atom Electron Configuration from the Periodic Table There are two ways to show the Quantum atom Electron Configuration. One way shows the number of electrons in the Principle Quantum Level (PEL) and Sublevel type (letter). The other way, known as BOX DIAGRAMS, show all four quantum numbers by using boxes for orbitals and arrows for electrons to show the opposite spin of the electrons.

Quantum Atom for Hydrogen Using the electron configuration from the periodic table, we will do both types. Quantum Atom for Hydrogen 1s1 # of electrons PEL SUBLEVEL (n)  

Using the electron configuration from the periodic table, we will do both types. Box Diagram for Hydrogen ORBITAL (box) 1s ARROW -SHOW SPIN of e-  PEL SUBLEVEL

RULES TO REMEMBER WHEN DRAWING BOX DIAGRAMS S has one orbital so draw 1 box P has 3 orbitals so draw 3 boxes, Each “P” box in a sublevel must have an electron before pairing up because each orbital has the same energy as the other orbitals (Boxes) Convention is to show the first arrow going up Electrons spin in opposite directions!

H He Li 1 1s1 2 1s2 2-1 1s2 2s1 Element Elec. Config. From P T Quantum Atom E. C. Box Diagrams H 1s He Li 1s 2s 1 1s1 2 1s2 2-1 1s2 2s1

Be B C 1s2 2s2 2-2 1s2 2s2 2p1 2-3 2-4 1s2 2s2 2p2 Element Elec. Config. From P T Quantum Atom E. C. Box Diagrams Be B C 1 s 2s 2p 1s2 2s2 2-2 1s2 2s2 2p1 2-3 2-4 1s2 2s2 2p2

N O F 2-5 1s2 2s2 2p3 1s2 2s2 2p4 2-6 1s2 2s2 2p5 2-7 Element Elec. Config. From P T Quantum Atom E. C. Box Diagrams N O F 1 s 2s 2p 2-5 1s2 2s2 2p3 1s2 2s2 2p4 2-6 1s2 2s2 2p5 2-7

Ne Na Mg Element Elec. Config. From P T Quantum Atom E. C. Box Diagrams Ne Na Mg

Element Elec. Config. From P T Quantum Atom E. C. Box Diagrams Al Si

Element Elec. Config. From P T Quantum Atom E. C. Box Diagrams P S

Element Elec. Config. From P T Quantum Atom E. C. Box Diagrams Cl Ar

Element Elec. Config. From P T Quantum Atom E. C. Box Diagrams K Ca

After argon (Ar) The energy levels begin to overlap and things get complicated. We will not be doing elements above Calcium. However…. How many orbitals are in the d sublevel? 5 f sublevel? 7 How many boxes would you draw for the d sublevel?

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