Electron Configurations You will need: 1.Your homework from Friday (Quantum Mechanical Model in last...

Electron Configurations

You will need: 1. Your homework from Friday (Quantum Mechanical

Model in last week’s packet)2. Your homework from last night (Electron

Configuration Guided Reading in this week’s packet)

Anything that you see in white, you should write down

Bohr Model of Hydrogen

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 331

Nucleus

Possible electron orbits

e

e

Bohr Model of Hydrogen

• Bohr model = epic fail for all other elements

e

e

The Quantum Mechanical Model

The Quantum Mechanical Model• 2 parts of an atoms

–Nucleus –Electron cloud

»Where the probability of finding an electron is high

»Drawn as a fuzzy cloud»The cloud is more dense where the

probability of finding the electron is high.

More likely to find an electron

Less likely to find an electron

Nucleus

Electron cloud

The Quantum Mechanical Model• Atomic Orbitals

–Space around the nucleus –High probability of finding an

electron –Has a specific energy level–Has a specific sublevel

»Sublevels have different shapes

• Further describes where an electron is likely to be found

The Quantum Mechanical ModelAtomic orbital shapes: AKA: Angular momentum quantum number

S orbital Angular momentum quantum number (l) = 0

The Quantum Mechanical ModelAtomic orbital shapes:

P orbitals Angular momentum quantum number (l) = 1


D orbitals Angular momentum quantum number (l) = 2


F orbitals Angular momentum quantum number (l) = 3

Think-Pair-Share • Turn to your neighbor and…

–Explain what an orbital is–List the 4 shapes of atomic orbitals

Vocabulary• Quantum numbers: tell us the properties of

atomic orbitals and the properties of electrons in the orbitals

• Principle quantum number – Symbol: n – The energy level that an electron occupies

• Angular momentum quantum number– Symbol: l– The shape of the orbital

• Spin quantum number – +1/2 or -1/2 – Spin state of an electron

Main energy level (n)

Sublevels (orbital shape)

Number of orbitals per sublevel

Number of electrons per sublevel

1 s 1 2

2

3

4





1 s 1 2

2 s 1 2

3

4





1 s 1 2

2 s 1 2

p 3 6

3

4





1 s 1 2

2 s 1 2

p 3 6

3 s 1 2

4





1 s 1 2

2 s 1 2

p 3 6

3 s 1 2

p 3 6

4


Sublevels(orbital shape)



1 s 1 2

2 s 1 2

p 3 6

3 s 1 2

p 3 6

d

4





1 s 1 2

2 s 1 2

p 3 6

3 s 1 2

p 3 6

d 5

4





1 s 1 2

2 s 1 2

p 3 6

3 s 1 2

p 3 6

d 5 10

4





1 s 1 2

2 s 1 2

p 3 6

3 s 1 2

p 3 6

d 5 10

4 s 1 2





1 s 1 2

2 s 1 2

p 3 6

3 s 1 2

p 3 6

d 5 10

4 s 1 2

p 3 6





1 s 1 2

2 s 1 2

p 3 6

3 s 1 2

p 3 6

d 5 10

4 s 1 2

p 3 6

d 5 10





1 s 1 2

2 s 1 2

p 3 6

3 s 1 2

p 3 6

d 5 10

4 s 1 2

p 3 6

d 5 10

f





1 s 1 2

2 s 1 2

p 3 6

3 s 1 2

p 3 6

d 5 10

4 s 1 2

p 3 6

d 5 10

f 7





1 s 1 2

2 s 1 2

p 3 6

3 s 1 2

p 3 6

d 5 10

4 s 1 2

p 3 6

d 5 10

f 7 14


• Electron configuration:– The arrangement of electrons in an atom

• The lowest-energy arrangement of the electrons for each element is called the element’s ground-state electron configuration

Rules for writing electron configurations

• Aufbau principle: – An electron occupies the orbital of lowest-

energy first

1s 2s 2p3s 3p 3d4s 4p 4d 4f5s 5p 5d 5f6s 6p 6d 6f


• Hund’s rule: – Electrons occupy equal energy orbitals one

at the time – The electrons in each orbital have the

same spin – School bus rule

2px 2py 2pz


• Pauli exclusion principle: –Electrons in the same orbital must

have different spins

2px 2py 2pz

Think Pair Share

• Turn to your neighbor and explain the three rules for electron configurations in your own words

Orbital Diagram p. 105

Box = orbital

Arrow = electron

Up and down arrow = electrons with opposite spins

Electron Notations • Orbital notation

– Lines (or boxes) represent orbitals – Arrows represent electrons

He

Writing Electron Configurations 1. Locate the element on the periodic table

Writing Electron Configurations

2. Determine the number of electrons in the element

1. Locate the element on the periodic table


3. Fill in the electrons in the orbital notation diagram starting at 1s (remember the rules)




4. Write the electron configuration from the completed orbital notation diagram





5. Calculate the number of electrons in the electron configuration and make sure it matches what you found in step 2

4. Write the electron configuration from the completed orbital notation diagram


2. Determine the number of electrons in an atom of the element


Orbital Notation

Aufbau principle: an electron occupies the orbital of lowest-energy first

Li =# of electrons = 3

Electron Notations • Electron configurations• Written in the following order:

1. Number of energy level2. Letter of sublevel 3. Number of electrons in each sublevel written as

a superscript 1s2Energy level

Sublevel

Number of electrons

1s22s22p6Energy levelsSublevels

Number of electrons



Li =1



Li =1s



Li =1s2



Li =1s22



Li =1s22s



Li =1s22s1

# of electrons = 3


C =

Hund’s rule: electrons occupy equal energy orbitals one at the time with the same spin

# of electrons = 6


C = 1



C = 1s



C = 1s2



C = 1s22



C = 1s22s



C = 1s22s2



C = 1s22s22



C = 1s22s22p



C = 1s22s22p2


# of electrons = 6


Ca = # of electrons = 20

Pauli exclusion principle: electrons in the same orbital must have different spins


Ca = 1



Ca = 1s



Ca = 1s2



Ca = 1s22



Ca = 1s22s



Ca = 1s22s2



Ca = 1s22s22



Ca = 1s22s22p



Ca = 1s22s22p6



Ca = 1s22s22p63



Ca = 1s22s22p63s



Ca = 1s22s22p63s2



Ca = 1s22s22p63s23



Ca = 1s22s22p63s23p



Ca = 1s22s22p63s23p6



Ca = 1s22s22p63s23p64



Ca = 1s22s22p63s23p64s



Ca = 1s22s22p63s23p64s2 # of electrons = 20



Cl = # of electrons = 17


Cl = 1


Cl = 1s


Cl = 1s2


Cl = 1s22


Cl = 1s22s


Cl = 1s22s2


Cl = 1s22s22


Cl = 1s22s22p


Cl = 1s22s22p6


Cl = 1s22s22p63


Cl = 1s22s22p63s


Cl = 1s22s22p63s2


Cl = 1s22s22p63s23


Cl = 1s22s22p63s23p


Cl = 1s22s22p63s23p5

Exit Ticket

• Fill out the worksheet that is being passed out

• Turn it in when you are finished • Begin working on tonight’s homework

– Save #4 for tomorrow night

sp

d (n-1)

f (n-2) 67

Blocks of the Periodic Table

1s

2s

3s

4s

5s

6s

7s

3d

4d

5d

6d

1s

2p

3p

4p

5p

6p

7p

4f

5f

1234567

Electron Notations • Noble gas notation

– The noble gas that comes before the desired element on the periodic table is written in brackets

– The rest of the electron configuration is written at the end • Energy level • Sublevel • Number of electrons

Sodium’s noble gas notation: [Ne]3s1Noble gas

Energy level Sublevel

Number of electrons


Fe = 1s


Fe = 1s2


Fe = 1s22


Fe = 1s22s


Fe = 1s22s2


Fe = 1s22s22


Fe = 1s22s22p


Fe = 1s22s22p6


Fe = 1s22s22p63


Fe = 1s22s22p63s


Fe = 1s22s22p63s2


Fe = 1s22s22p63s23


Fe = 1s22s22p63s23p


Fe = 1s22s22p63s23p6


Fe = 1s22s22p63s23p64


Fe = 1s22s22p63s23p64s


Fe = 1s22s22p63s23p64s2


Fe = 1s22s22p63s23p64s23


Fe = 1s22s22p63s23p64s23d


Fe = 1s22s22p63s23p64s23d6


Electron Configurations You will need: 1.Your homework from Friday (Quantum Mechanical Model in last...

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