1

Bellringer (Friday 11/7/08) Write the question and answer.

1. Compare and Contrast the size and energy of 1S, 2S and 3S.

2. How many energy levels are there on the periodic table?

2Relative sizes of the spherical 1s, 2s, and 3s orbitals of hydrogen.

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Energy LevelsEnergy LevelsEnergy LevelsEnergy Levels

n = 1n = 1

n = 2n = 2

n = 3n = 3

n = 5n = 5n = 4n = 4

n = 6n = 6n = 7n = 7

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Arrangement of Arrangement of Electrons in AtomsElectrons in Atoms

Arrangement of Arrangement of Electrons in AtomsElectrons in Atoms

Electrons in atoms are arranged asElectrons in atoms are arranged as

LEVELSLEVELS (n) (n)

SUBLEVELSSUBLEVELS (l) (l)

ORBITALSORBITALS (m (mll))

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QUANTUM NUMBERSQUANTUM NUMBERSQUANTUM NUMBERSQUANTUM NUMBERS

The The shape, size, and energyshape, size, and energy of each orbital is a function of each orbital is a function of 3 quantum numbers which describe the location of of 3 quantum numbers which describe the location of an electron within an atom or ionan electron within an atom or ion

n n (principal)(principal) ---> energy level---> energy level

ll (orbital) (orbital) ---> shape of orbital---> shape of orbital

mmll (magnetic)(magnetic) ---> designates a particular ---> designates a particular suborbitalsuborbital

The fourth quantum number is not derived from the The fourth quantum number is not derived from the wave functionwave function

ss (spin)(spin) ---> spin of the electron ---> spin of the electron (clockwise or counterclockwise: ½ or – ½)(clockwise or counterclockwise: ½ or – ½)

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Energy LevelsEnergy LevelsEnergy LevelsEnergy Levels

• Each energy level has a number Each energy level has a number called thecalled the PRINCIPAL PRINCIPAL QUANTUM NUMBER, nQUANTUM NUMBER, n

• Currently n can be 1 thru 7, Currently n can be 1 thru 7, because there are 7 periods on because there are 7 periods on the periodic tablethe periodic table

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Types of Orbitals

• The most probable area to find The most probable area to find these electrons takes on a shapethese electrons takes on a shape

• So far, we have 4 shapes. They So far, we have 4 shapes. They are named s, p, d, and f. are named s, p, d, and f.

• No more than 2 e- assigned to an No more than 2 e- assigned to an orbital – one spins clockwise, one orbital – one spins clockwise, one spins counterclockwisespins counterclockwise

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Types of Orbitals Types of Orbitals ((ll))

s orbitals orbital p orbitalp orbital d orbitald orbital

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p Orbitalsp Orbitalsp Orbitalsp Orbitals

Sublevel p has 3 orbitals with 6 electrons.Sublevel p has 3 orbitals with 6 electrons.

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The shapes and labels of the five 3d orbitals.

Sublevel d has 5 orbitals with 10 electronsSublevel d has 5 orbitals with 10 electrons

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f Orbitalsf Orbitalsf Orbitalsf Orbitals

For l = 3, For l = 3, ---> f sublevel with 7 orbitals ---> f sublevel with 7 orbitals

and 14 electronsand 14 electrons

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s orbitalss orbitals d orbitalsd orbitals

Number ofNumber oforbitalsorbitals

Number of Number of electronselectrons

p orbitalsp orbitals f orbitalsf orbitals

How many electrons can be in a sublevel?How many electrons can be in a sublevel?

Remember: A maximum of two electrons can be placed in an orbital.

11 33 55 77

22 66 1010 1414

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Sublevels =blocks(Types of orbitals)

Quantum Number

Principal Energy Level Layout p. 155Principal Energy Level Layout p. 155# of orbitals

related to sublevel

1

2

3

4

s

s

1

p

spd

13

135

spdf

1357

14Orbitals and the Orbitals and the Periodic TablePeriodic Table

• Orbitals grouped in s, p, d, and f orbitals Orbitals grouped in s, p, d, and f orbitals (sharp, proximal, diffuse, and fundamental)(sharp, proximal, diffuse, and fundamental)

s orbitalss orbitalsp orbitalsp orbitals

d orbitalsd orbitals

f orbitalsf orbitals

15Electron Configurations Be able to explain this on a

test.

2p4

Energy LevelEnergy Level

SublevelSublevel

Number of Number of electrons in electrons in the sublevelthe sublevel

1s1s22 2s 2s22 2p 2p66 3s 3s22 3p 3p66 4s 4s22 3d 3d1010 4p 4p66 5s 5s22 4d 4d1010 5p 5p66 6s6s22 4f 4f1414…… etc.etc.

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Underwater HotelTry it out!

• If you are a visual learner – try this method

17Diagonal Rule

ss

s 3p 3ds 3p 3d

s 2ps 2p

s 4p 4d 4fs 4p 4d 4f

s 5p 5d 5f 5g?s 5p 5d 5f 5g?

s 6p 6d 6f 6g? 6h?s 6p 6d 6f 6g? 6h?

s 7p 7d 7f 7g? 7h? 7i?s 7p 7d 7f 7g? 7h? 7i?

11

22

33

44

55

66

77

Steps:Steps:

1.1. Write the energy levels top to bottom.Write the energy levels top to bottom.

2.2. Write the orbitals in s, p, d, f order. Write Write the orbitals in s, p, d, f order. Write the same number of orbitals as the energy the same number of orbitals as the energy level.level.

3.3. Draw diagonal lines from the top right to the Draw diagonal lines from the top right to the bottom left.bottom left.

4.4. To get the correct order, To get the correct order,

follow the arrows!follow the arrows!

By this point, we are past By this point, we are past the current periodic table the current periodic table so we can stop.so we can stop.

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Why are d and f orbitals always in lower energy levels?

• d and f orbitals require LARGE amounts of energy

• It’s better (lower in energy) to skip a sublevel that requires a large amount of energy (d and f orbtials) for one in a higher level but lower energy

This is the reason for the diagonal rule! BE SURE TO FOLLOW THE ARROWS IN ORDER!

19Let’s Try It!

• Write the electron configuration for the following elements:

Br

Sr

Sb

Re

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Shorthand Notation

• A way of abbreviating long electron configurations

• Since we are only concerned about the outermost electrons, we can skip to places we know are completely full (noble gases), and then finish the configuration

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Shorthand Notation

• Step 1: It’s the Showcase Showdown!Find the closest noble gas to the atom (or ion), WITHOUT GOING OVER the number of electrons in the atom (or ion). Write the noble gas in brackets [ ].

• Step 2: Find where to resume by finding the next energy level.

• Step 3: Resume the configuration until it’s finished.

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Shorthand Notation• Chlorine

– Longhand is 1s2 2s2 2p6 3s2 3p5

You can abbreviate the first 10 electrons with a noble gas, Neon. [Ne] replaces 1s2 2s2 2p6

The next energy level after Neon is 3

So you start at level 3 on the diagonal rule (all levels start with s) and finish the configuration by adding 7 more electrons to bring the total to 17

[Ne] 3s2 3p5

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BellringerPractice Shorthand

Notation• Write the shorthand notation for each

of the following atoms:1. Cl2. K3. Ca

Take out electron practice and periodic table handouts.

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Orbital Diagrams

• Graphical representation of an electron configuration

• One arrow represents one electron

• Shows spin and which orbital within a sublevel

• Same rules as before (Aufbau principle, two electrons in each orbital, etc.)

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Valence ElectronsValence ElectronsValence ElectronsValence ElectronsElectrons are divided between core and Electrons are divided between core and

valence electronsvalence electronsB 1sB 1s22 2s 2s22 2p 2p11

Core = [He]Core = [He] , , valence = 2svalence = 2s22 2p 2p11

Br [Ar] 3dBr [Ar] 3d1010 4s 4s22 4p 4p55

Core = [Ar] 3dCore = [Ar] 3d1010 , , valence = 4svalence = 4s22 4p 4p55

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Rules of the GameRules of the GameRules of the GameRules of the GameNo. of valence electrons of a main group No. of valence electrons of a main group

atom = Group numberatom = Group number (for A groups) (for A groups)

Atoms like to either empty or fill their outermost Atoms like to either empty or fill their outermost level. Since the outer level contains two s level. Since the outer level contains two s electrons and six p electrons (d & f are always in electrons and six p electrons (d & f are always in lower levels), the optimum number of electrons lower levels), the optimum number of electrons is eight. This is called the is eight. This is called the octet rule.octet rule.