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FACT:. Chemical reactions happen because electrons are shared or transferred from one substance to another. Write a mathematical equation that allows us to predict the Max # of electrons if we know the energy level (n). Max # = …n…. Equation to calculate Max # of e -. 2 n 2.

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Presentation Transcript
FACT:

Chemical reactions happen

because

electrons are shared

or transferred from

one substance to another

Write a mathematical equation that allows us to predict the Max # of electrons if we know the energy level (n)

Max # = …n…

Equation to calculate Max # of e-

2n2

Where n is any energy level

There are 4 Quantum #s and

those #s are used to describe where an electron is likely to be found at any given time

This is a lot like being able to use four “places” to describe EXACTLY where Mrs. BB-G should be at 7:00AM on Friday.

The Principle

Quantum # = n

The first number

(a.k.a. The Electron

Energy level)

Specifies the electron energy level that the electron is on

Principle Quantum #

n = 1, 2, 3, 4, 5, 6, 7

2nd Floor

ℓ = s, p, d, f

### 2nd Quantum # = ℓ

Specifies the shape of the orbital or

sub-energy level

2nd Quantum #

Students (sleeping) (s)sitting prone at desk (p)“darn” I have to sit up (d)forget this standing up in class (f)

ℓ = s, p, d, f

p

d

f

s

3rd Quantum # = m

m = x,y,z

3-d World

Like tables arranged at different angles in the classroom

4th Quantum # = ms

ms = + ½or–½

Clockwise or counterclockwise

Specifies the

electron’s spin

+

QUANTUM

NUMBERS

n ---> shell 1, 2, 3, 4, ...

l ---> subshell s,p,d,f

ml ---> orbital x,y,z ( 3-D)

ms ---> electron spin

PERIODS
• The number of each period shows the principal energy level

1

2

3

4

5

6

7

Lanthanide 4f

Actinide 5f

PERIODS
• Horizontal rows of the table are called periods or rows.
GROUPS
• The vertical columns of the Periodic Table are called groups or families.

lA

0

1

lllA

lVA

VA

VIA

VlIA

llA

2

3

lllB

lVB

VB

VlB

VllB

VlllB

lB

llB

4

5

6

7

Groups

At F O N Home

18

1

Diatomic Elements

H2 N2 O2F2Cl2Br2I2

2

13

14

15

16

17

Transition Metals

9

3

4

5

6

7

8

10

11

12

NON-METALS

METALS

METALLOIDS

DIAGONAL RULEOrder of Filling orbitals due to increasing energy (Lowest energy level – 1)
• Draw a diagram putting each

energy shell on a row .

• Listing the orbitals,

(s, p, d, f), (left-to-right)

1s

2s 2p

3s 3p 3d

4s 4p 4d 4f

5s 5p 5d 5f

6s 6p 6d

7s 7p

• Next, draw arrows through

the diagonals, looping back

to the next diagonal each time

Aufbau Principleelectrons will fill orbitals of lowest energy first, then fill according to increasing energy.

Diagonal Rule
• Steps:
• Write the energy levels top to bottom.
• Write the orbitals in s, p, d, f order. Write the same number of orbitals as the energy level.
• Draw diagonal lines from the top right to the bottom left.
• To get the correct order, follow the arrows!

1

2

3

4

5

6

7

s

s 2p

s 3p 3d

s 4p 4d 4f

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

s 5p 5d 5f 5g?

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

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

Where is Ag on the Per. Table?

1s2

2s2

2p6

3s2

3p6

3d10

4s2

4p6

4d10

4f14

5s2

5p6

5d10

5f14

6s2

6p6

6d10

• Ag
• 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s24d9

7s2

7p6

### ORBITAL

2 e-

6 e-

Space occupied by a pair of electrons

10 e-

14 e-

### So why do electrons fill in like they do?

Why is K’s last electron in the 4th energy level?

### 2 Factors Influencing Electron Placement

• Energy Level
• - Closer to nucleus=easy

2. Orbital or Subenergy

level (shape) - spdf

### Electron Configuration

A detailed way of showing the order

in which electrons

fill in around the nucleus

What element is this?

# of e- in sub-energy level

### Electron Configuration Symbols

5f3

Sub-Energy Level

Energy Level

Electron Configurations

What element

is this?

2p4

Number of electrons in the sublevel

Energy Level

Sublevel

Electron Configuration

2p4

4f14

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14…etc.

Writing Electron Configurations
• Strategy: start with hydrogen, and build theconfiguration one electron at a time(Aufbau principle)
• 1. In the H put 1s1; above He put 1s2; in Li 2s1, Be 2s2, In B put 2p1; in C put 2p1; etc across the chart.
• 2. Fill subshells in order by counting across periods, from hydrogenup to the element of interest:

PERIODIC TABLE WORKSHEET

Give the location of the last electron for all of the elements on the periodic table below.

1s2

1s1

2s1

2p1

2p2

2s2

4s2

3d1

5d1

5d5

6p3

5f1

Bohr Models

vs.

Electron Configurations

K

K 19e-

K:

1s2

3s2

3p6

4s1

2p6

2s2

1s1

### Write the e-config for:

1s2

He:

Li:

1s22s1

H:

K:

1s22s22p63s23p64s1

Al:

1s22s22p63s23p1

K:

1s22s22p63s23p64s1

### Noble Gas Shortcut

K:

[Ar] 4s1

So what is different?

Electron Configuration fromthe Periodic Table

8A

1A

1

2

3

4

5

6

7

3A

4A

5A

6A

7A

2A

Ne

P

3s2

3p3

P = [Ne]3s23p3

P has 5 valence electrons

Electron Configuration fromthe Periodic Table

8A

1A

1

2

3

4

5

6

7

3A

4A

5A

6A

7A

2A

3d10

Ar

As

4s2

4p3

As = [Ar]4s23d104p3

As has 5 valence electrons

Noble Gas Configuration

• Find the symbol for the element zinc. [Zn]

2. Write the symbol in brackets for the nearest, smaller noble gas. [Ar]

3. Write the outer electron configuration for the

remaining electrons.

[Ar] 4s2 3d10

1s22s22p63s23p4

Ex. 1.S

[Ne]3s23p4

1s22s22p63s23p64s23d104p65s24d105p66s24f145d4

2. W

[Xe]6s24f145d4

### Orbital Notation

Electrons are distributed in the electron cloud into:

principal energy levels(1, 2, 3, 4, 5, 6, 7),

sublevels (s, p, d, f),

orbitals (s has 1, p has 3, d has 5, f has7)

and

spin(2 electrons allowed per orbital).

### Arrow-Orbital Notation

A way to show orbital filling, spin, relative energy

Fluorine’s Orbital notation

s = ____ ( One orbital / 1 line)

p = ____ ____ ____ ( 3 orbitals/ 3 lines)

d = ____ ____ ____ ____ ____ ( 5 orbitals/ 5 lines)

f = ____ ____ ____ ____ ____ ____ ____ ( 7 orbitals/ 7 lines)

unoccupied

orbital

orbital with

1 electron

orbital with

2 electrons

Orbital Diagrams
• an orbital is represented as a square and the
• electrons in that orbital as arrows
• the direction of the arrow represents the spin of the electron

1s

2s

2p

3s

3p

Example – Write the Orbital Diagram and Electron Configuration ofMagnesium.

1. Draw 9 boxes to represent the first 3 energy levels s andp orbitals

Example – Write the Orbital Diagram and Electron Configuration ofMagnesium.

2. Add one electron to each box in a set, then pair the electrons before going to the next set until you use all the electrons

• When pair, put in opposite arrows







1s

2s

2p

3s

3p



1s



2s



2p







3s

3p

Example – Write the Ground State Orbital Diagram and Electron Configuration of Magnesium.

3. Use diagram to write the electron configuration

• Write the number of electrons in each set as a superscript next to the name of the orbital set

1s2 2s2 2p63s2= [Ne]3s2

Arrow-Orbital Diagrams

What is this element?

Energy

3d

4s

3p

3s

2p

2s

1s

### Lewis Electron Dot Diagrams

The easiest way to represent the # of valance electrons

Lewis Structures

Find your element on the periodic table.

Determine the number of valence electrons.

P = E

This is how many electrons you will draw.

Lewis Structures
• Find out which group (column) your element is in.
• This will tell you the number of valence electrons your element has.
• You will only draw the valence electrons.

www.chem4kids.com

Groups - Review

Group 8 = 8 electrons

Group 1 = 1 electron

Except for He, it has 2 electrons

Group 2 = 2 electrons

3,4,5,6,7

• Each column is called a “group”
• Each element in a group has the same number of electrons in their outer orbital, also known as “shells”.
• The electrons in the outer shell are called “valence electrons”

www.chem4kids.com

ELECTRON DOT DIAGRAMS:visual representations of elements and their valence electrons

Standard form:

3

6

R

4

1

7

2

5

8

Order of electron/dot placement

element symbol

Example:

O

6 valence electrons

Oxygen

Outer shell e- (s)

Outer shell

electrons

Gain/lose e-

charge

Group 1

s1

1 outer shell e-

Lose 1e-

+1

Group 2

s2

2

Lose 2e-

+2

Group 13

s2p1

3

Lose 3e-

+3

Group 14

s2p2

4

Lose 4e- or

Gain 4e-

+4

-4

Group 15

s2p3

5

Lose 3e-

-3

Group 16

s2p4

6

Lose 2e-

-2

Group 17

s2p5

7

Lose 1e-

-1

Group 18

s2p6

8

Full octet

Valence electrons:electrons that are in the outermost shell

(unfilled orbitals) (outer shell electrons) [s + p] e- (s)

6th

3rd

4th

Symbol

2nd

7th

1st

5th

8th

Fill in Electron Dots

Lewis Dot Diagram

Ex: Px

Py X s

Pz

What up?

Why will you never have more than eightdots?

3

6

Kr

4

2

7

1

This is called theoctet rule.

5

8

Lewis Structures

C

Write the element symbol.

Carbon is in the 4th group, so it has 4 valence electrons.

Starting at the right, draw 4 electrons, or dots, counter-clockwise around the element symbol.

Lewis Structures

H

Try these elements

• H
• P
• Ca
• Ar
• Cl
• Al
Lewis Structures

P

Try these elements

• H
• P
• Ca
• Ar
• Cl
• Al
Lewis Structures

Ca

Try these elements

• H
• P
• Ca
• Ar
• Cl
• Al
Lewis Structures

Ar

Try these elements

• H
• P
• Ca
• Ar
• Cl
• Al
Lewis Structures

Cl

Try these elements

• H
• P
• Ca
• Ar
• Cl
• Al
Lewis Structures

Al

Try these elements

• H
• P
• Ca
• Ar
• Cl
• Al

### Valence Electrons

Electrons in the outermost energy level

(involved in chemical reactions)

Valence Electrons

Electrons are divided between core and valence electrons

B 1s2 2s2 2p1

Core = [He] , valence = 2s2 2p1

Br [Ar] 3d10 4s2 4p5

Core = [Ar] 3d10 , valence = 4s2 4p5

Keep an Eye On Those Ions!
• Tin

Atom: [Kr] 5s2 4d10 5p2

Sn+4 ion: [Kr] 4d10

Sn+2 ion: [Kr] 5s2 4d10

Note that the electrons came out of the highest energy level, not the highest energy orbital!

Keep an Eye On Those Ions!
• Bromine

Atom: [Ar] 4s2 3d10 4p5

Br- ion: [Ar] 4s2 3d10 4p6

Note that the electrons went into the highest energy level, not the highest energy orbital!

Keep an Eye On Those Ions!
• Electrons are lost or gained like they always are with ions…
• negative ions have gained electrons, positive ions have lost electrons
• The electrons that are lost or gained should be added/removed from the highest energy level (not the highest orbital in energy!)
Valence Electrons

Rb = 37 electrons = 1s22s22p63s23p64s23d104p6 5s1

• the highest principal energy shell of Rb that contains electrons is the 5th, therefore Rb has 1 valence electron and 36 core electrons

Kr = 36 electrons = 1s22s22p63s23p64s23d104p6

• the highest principal energy shell of Kr that contains electrons is the 4th, therefore Kr has 8 valence electrons and 28 core electrons

### Quantum Review

1st Q# Principle (n) : Energy Level

2nd Q# (ℓ): Shape of sub (s,p,d,f)

3rd Q# (m) : Orientation of Orbital

(3-D x,y,z)

4th Q#(ms): Spin of e- (Clockwise/counterclockwise)

### AufbauPrinciple

All lower energy sublevels must be full before high energy sublevels begin filling in

1s

2s 2p

3s 3p 3d

4s 4p 4d 4f

5s 5p 5d 5f

6s 6p 6d

7s 7p

### Pauli Exclusion Principle

An atomic orbital can only hold 2 electrons

Each electron has its own spin.

### Hund’s Rule

Within the same sublevel, electrons fill empty orbitals first,

then complete the half filled orbitals