chem-quantum

(1)

(2)

Some background

(3)

(4)

First part of the answer:

You can never exactly “find” an electron, because electrons behave like blobs (waves) NOT particles

Particle Blob (wave)

You can exactly where it is They bounce off each other They will go through one slit

Its fuzzy Bounce?

(5)

You can never exactly find an electron, you can only ask

“what is the probability of finding an electron at a certain point”

Really high probability

(6)

Rather than draw a fuzzball, we find the “90% probability shell”. Inside this shell, there is a 90% chance of finding the electron

Inside this red sphere there Is a 90% chance the electron Is there… that is as good as You can get.

You can NEVER say that an Electron is EXACTLY in one place

(7)

Can have really crazy shapes

(8)

(9)

ˆH

y =

E

y

The shape of the orbital comes from the solution to this crazy equation call the Schrodinger Equation

An “operator” in mathematics

energy

“psi”-- a complicated three dimensional

mathematical function

y

2

(10)

(11)

An orbital can be described by:

1) Its size

(12)

An orbital can be described by:

1) Its size

We use a number: n=1 2 3 4 5… the bigger the number, the Bigger the orbital

1) Its shape

We use a letter: s p d f (historical--from spectroscopy)

s sphere

(13)

To designate an orbital, we just need to specify n and s, p or d

1s

2s 2p

3s 3p 3d

(14)

Last thing….

Every orbital has an associated energy, E. Good rule of thumb:

the bigger and weirder, the higher the energy

(15)

ˆH

y =

E

y

When you solve the Schrodinger Equation, you get “psi” AND E, the energy of the orbital

An “operator” in mathematics

The orbital energy

“psi”-- a complicated three dimensional

mathematical function

y

2

(16)

Where are the electrons?

(17)

1) We want to know where the electrons are in atoms

2) Electrons live in funny shaped blobs with different sizes 3) The funny shaped blobs are called orbitals

4) Each orbital has a different energy

(18)

We want to answer a simple question: Consider a chlorine atom

17 protons and 17 electrons

Where are the electrons?

x

y z

nucleus

e

-e

-Do they just buzz around?

(19)

(20)

Some rules to the game:

We denote electrons with an arrow

The arrow can point up or down

Electrons are LAZY: they seek the lowest energy

Electrons are ANTI-SOCIAL: they like to be by themselves.

(21)

Lets fill boxes with arrows!

Rules:

1) We denote a single electron with an arrow

2) Electrons fill up the lowest energy orbital available 3) A maximum of two electrons can fit in an orbital

4) If they can find a way to NOT both go into one, THEY WILL

5) If they do both go into one, we write it like this

(22)

What are the boxes? Umm….quantum mechanical orbitals… More on that later….

1s

2s

2p

3d

s orbitals: max of two electrons Can fit

p orbitals: max of 6 electrons

(23)

E 1s 2s 2p 3s 3p 3d 4s 4p 4d 5s 5p

Quick Summary: We are figuring out WHERE the Electrons are in atoms. We use this table to do it. Each box is an orbital

Two electrons max in an orbital

Electrons are more lazy than antisocial

orbital

(24)

E 1s 2s 2p 3s 3p 3d 4s 4p 4d 5s 5p

Once we have the boxes filled, we can write an ELECTRONIC STRUCTURE

(25)

Li Be B C N O F Ne

(26)

(27)

We can use a more compact notation

Al 13 electrons 1s22s22p63s23p1

This part of its electronic

configuration is the same as neon!

(28)

The electronic structure of ANY atom can be written as

Electronic structure of

previous noble gas Additional stuff

1s22s22p63s23p1

(29)

Na Mg Al Si P S Cl Ar

Work it out on your own….

(30)

E 1s 2s 2p 3s 3p 3d 4s 4p 4d 5s 5p

Super Electron Filling Table

Argon filled

1s22s22p63s23p6 [Ar]

Look at what is coming next…. 4s3d4p…

(31)

Potassium K 19 electrons

1s22s22p63s23p64s1 [Ar]4s1

The 4s gets filled

next--Electronic structure of

(32)

(33)

(34)

(35)

You can see how the periodic table fills up… certain

regions have their p-orbitals filled, others have d-regions filled.

(36)

2s 3s 4s 5s 6s 3d 4d 5d 6d 7s 2p 3p 4p 5p 6p 4f 5f

(37)

2s 3s 4s 5s 6s 3d 4d 5d 6d 7s 2p 3p 4p 5p 6p 4f 5f

(38)

F 9e-

Al 13e

-Ar 18e

-Ca 20e

-V 23e

-Zn 30e

-As 33e

-Sr 38e

-Mo 42e

-Ag 47e

(39)

1) Ba 56 2) Tc 43 3) Cl 17 4) I 53 5) Sr 38

6) Mn 25 7) Ni 28 8) Ag 47 9) La 57 10) Sb 51

Two points each!

(40)

Quiz: Figure out the electron configuration for the following. You can use

shorthand-F 9e-

Al 13e

-Ar 18e

-Ca 20e

-V 23e

-Zn 30e

-As 33e

-Sr 38e

-Mo 42e

(41)

(42)

Recall: Sure Bets

h a

b c d

e

g

+1 +2 +3 -2 -1

A B C D E F G H Hydrogen Alkali metals

(43)

Recall: Ions

When a neutral atom loses or gains ELECTRONS, it becomes an ION

e.g., losing an electron: Sodium loses an electron to become a cation

_Na

¾ ®

¾

_Na

+

_e

-Mg

¾ ®

¾

___

+

___

K

¾ ®

¾

____

+

___

e.g., gaining an electron: Chlorine gains an electron to become an anion

Cl

+

e

-

¾ ®

¾

Cl

-F

+

___

¾ ®

¾

___

O

+

___

¾ ®

¾

___

(44)

Write the shorthand electronic structure for the following atoms Li

(45)

Write the chemical equation for the formation of the

(46)

Write the electronic structure of

(47)

Write the electronic structure of the following IONS

Li+

Na+

K+

Be2+

Mg2+

Ca2+

Al3+

O

2-F

(48)

E n=1 n=2 n=3 n=4 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f n=5 5s 5p 5d 5f

(49)

Try it out..

(50)

E 1s 2s 2p 3s 3p 3d 4s 4p 4d 5s 5p

FLAME TEST LAB!

orbital

E=(a constant named after a dude called planck)(color of the light)

Dip wire in acid

Drip a couple drops on wire Stick wire in flame

Record color-- use crayons You will be marked on how carefully

(51)

E

1s 2s

2p

3s

3p

3d 4s

4p

4d 5s

5p

(52)

E

1s 2s

2p

3s

3p

3d 4s

4p

4d 5s

5p

(53)

E

1s 2s

2p

3s

3p

3d 4s

4p

4d 5s

5p

(54)

E

1s 2s

2p

3s

3p

3d 4s

4p

4d 5s

5p

(55)

E

1s 2s

2p

3s

3p

3d 4s

4p

4d 5s

5p

(56)

The other part of quantum mechanics…

D

E

=

h

n

D

E

=

h

c

l

(57)

E

1s 2s

2p

3s

3p

3d 4s

4p

4d 5s

5p

Do it for sodium

(58)

Now stick a small chunk of sodium in a fire

Woah. Pretty colors. Always Screaming orange/yellow.

(59)

(60)

E

1s 2s

2p

3s

3p

3d 4s

4p

4d 5s

5p

Do it for sodium

(61)

E 1s 2s 2p 3s 3p 3d 4s 4p 4d 5s 5p

Do it for sodium

orbital q

The lone 3s electron Hops up to the 3p Because of the heat This is called an

(62)

E 1s 2s 2p 3s 3p 3d 4s 4p 4d 5s 5p The excited sodium atom rises in the flame… and the excited electron goes back To its original 3s orbital.

(63)

E 1s 2s 2p 3s 3p 3d 4s 4p 4d 5s 5p The electron is going from a high energy orbital to a low energy one-- it needs

To release its energy…. It does so by shooting out a little blip of light… Like a spark. This blip of light is called a photon.

orbital

Blip of light

(64)

E 1s 2s 2p 3s 3p 3d 4s 4p 4d 5s 5p

The color of the light is special….

orbital

Blip of light

Note the color…

(65)

650 nm 590 nm 570 nm 510 nm 475 nm 445 nm 400nm

Wavelengths are reported in… nm… nanometers 109 nm = 1 m

l

The color of light is given by its wavelength

(66)

The frequency of light is given by this…

n =

c

l

Speed of light

(67)

Speed of light

Recall, this is the speed that a photon travels at

c

=

3 ´

10

8 m / s

(68)

Converting between wavelength and frequency

n =

c

l

Step 1: convert wavelength in nm to wavelength in m

650nm

1m

10

9

nm

æ

èç

ö

ø÷

=

6.5 ´

10

-7

m

Step 2: pop this in the frequency equation

n =

c

l

=

3 ´

10

8

m / s

6.5 ´

10

-7

m

=

4.615 ´

10

(69)

l

650 nm 590 nm 570 nm 510 nm 475 nm 445 nm 400nm

For each color in the visible spectrum, calculate the

Frequency of the light

(70)

E 1s 2s 2p 3s 3p 3d 4s 4p 4d 5s 5p The final connection….

The electron jumped DOWN from the 3p to 3s. It shot a blip Of light out (a photon). The color of the light is related to its Frequency and wavelength.

orbital

Blip of light

Note the color…

DE = E_3p - E_3s

(71)

Light and Energy….

It turns out.. That energy and light are very closed related…. High frequency light…. High energy…..

Low frequency light…. Low energy….

D

E

=

h

n

h= 6.62 × 10

-34

Js

Planck’s Constant

Energy difference between the excited orbital and the lower one

(72)

Stick sodium in a fire

A screaming yellow flame is observed.

What is the delta E for the orbitals involved?

570nm 1m 109_nm

æ

èç öø÷ = 5.7 ´10-7m Step 1: Convert nm to m

Step 2: Convert lto n Step 3: Convert nto DE

n = c l =

3´108_{m / s}

(73)

Stick copper in a fire

A screaming green flame is observed.

Step 1: Convert nm to m

(74)

Stick strontium in a fire

A screaming red flame is observed.

(75)

Stick potassium in a fire

A screaming red flame is observed.

(76)

Flame Tests Lab

Groups of 2 or three. You will have a bunsen burner, crayons, some acid, and some vials.

Your goal will be to predicted the DE based on the flame colors. You will try three samples.

(one person in group writes this)

Introduction: discuss 1)safety 2)goal of experiment 3) all key equations 4) define all variables in equations.

Complete sentences and proper grammar MUST be used. Any point form stuff will get ZERO

(another one)

Procedure: 5 separate steps.

(another group member does this)

Results: One large data table. Three trials. Large enough that you can include a COLOR DIAGRAM of the flame, the wavelength in nm, frequency in s-1_{and delta E in J.}

Conclusion: Three complete sentences. One sentence must have a semi colon.

D

E

=

h

n

Grading:

5 points technique (clean up) 5 points data (data table) 5 points calculations (units)

(77)

Friday Quiz

1) Write the shorthand electronic structure for sodium 2) What happens when sodium is in a flame?

3) A photon is a proton T/F

4) A photon has a specific color

5) In the excited state for Sodium, the electron in the 3s orbital jumps to the 3p. Write the shorthand electronic structure for sodium in the excited

state.

6) How fast does a photon go?

7) Wavelength is given by (funny greek thing) 8) Frequency is given by (funny greek thing)

9) Write down Planck’s Constant (h). Include units. 10) Yellow light has what wavelength?

11) Is this equation correct? T/F

12) Wavelength is closely related to color T/F

13) is an energy difference and has the units of nm T/F

14) Photons are emitted when an electron goes up to a higher box T/F 15) A photon goes in one direction T/F

D

E

=

h

l

(78)

Radioactivity Quiz

1) The mass of the nucleus comes from protons and neutrons (T/F) 2) The ______ force holds the nucleus together

3) protons and neutrons stick together when they are very close (T/F) 4) Neutrons stabilize orbitals (T/F)

5) As the atomic number is increased, the ratio of protons to neutrons in the nucleus __________

6) The charge of an beta particle is -1 (T/F) 7) The symbol for a beta particle is _______

8) When a neutron turns into two electrons and a proton, the result is a beta particle (T/F)

9) Alpha particles and gamma rays are not dangerous (T/F) 10) The symbol for a alpha particle is _________

11) The beta particle is an electron that resides in the 4s orbital (T/F) 12) What is the symbol for a gamma ray?

13) Which type of radioactivity is the least dangerous?

14) The wavelength of gamma rays is extremely short (T/F)

(79)

Final Workshop

I am holding your points from the lab hostage. They are now Participation points. Give me 150% effort, and you get to keep Them…

If I have to ask for your attention, or ask for you get on board, I Will snip away as I feel fit…

All of this is posted on the website

Do not waste time writing the questions down. Just work Out the answers.

This workshop has been designed to help you study. I will be asking for you to do a lot. If I get any whining about having to write

(80)

Electronic Structure

Draw a new super electron filling table up to 4s

Quick-- short hand electronic structure for (I will pick at random) Ni

C S Ca

(81)

Ions

What are valance electrons?

What orbitals do valence electrons come from?

Draw an orbital cartoon for carbon. Label all the orbitals.

Hmm… write the shorthand electronic structure for the C4+ ion

How about F

-O

2-Mg2+

(82)

Excited States

Produce another super electron filling table up to 4p Write the shorthand electronic structure for Na

Fill the super electron filling table for Na

Stick Na in a flame. Show on the filling table the possible excited State. Write the electronic structure of this excited state.

(83)

E 1s 2s 2p 3s 3p 3d 4s 4p 4d 5s 5p orbital q

Remove the sodium from the flame What happens to the electron?

(84)

E 1s 2s 2p 3s 3p 3d 4s 4p 4d 5s 5p

How fast does the photon go? Label DeltaE on this plot

orbital

Blip of light

(85)

445 nm 590 nm 510 nm 475 nm 650 nm

400nm 570 nm

l

(86)

l

Show what a single wavelength is For

each--Which color

(87)

445 nm 590 nm 510 nm 475 nm 650 nm 400nm 570 nm

Calculate the frequency for each Wavelength

Which one has the highest frequency?

(88)

Bonding: Two types Ionic:

Covalent:

NaCl

O₂

(89)

Ionic Bonding-- dot’s n arrows

Elements ions dream fantasy compound dots n’ arrows Al

Br Ga O Sr Cl

(90)

Covalent Bonding-- loops

F F

Cl N Cl Cl

O

S O O

H

H C C N H

N N

O S O

O C O

H N N N O I O

(91)

Draw a new super electron filling table up to 4s

Quick-- short hand electronic structure for (I will pick at random) Ni

C S Ca

(92)

The blip of light is called a “photon”

(93)

(94)

(95)

(96)

Light is an oscillating electromagnetic field Thanks. That’s a lot of help.

How about this: We don’t know what it is, but we know when its there.

How about this: We don’t know what it is, but a proton Will shake back and forth when the photon hits

(97)

Depends on the color of Light of the photon!

Slow

Medium

(98)

Slow

Medium

fast

The frequency of the light determines its color.

The color of the light determines how fast the proton will shake Frequency (s-1_{or Hz)}

4.615 X 1014

5.26 X 1014

7.5 X 1014

Nasty numbers, But notice the Trend

Higher frequency, But notice the trend…

(99)

The photon also has a “wavelength”

The photon Moves at the Speed of light 3 X 108 m/s

In fact, as this “wave” passes over the proton At the speed of light, the proton “rides along” With the wave…like surfing

The wavelength is the length of one wave, reported in nm

(100)

The wavelength is the color

“long” wavelengths makes the proton gently Shake back and forth

“short” wavelengths makes the proton shake Really fast…

(101)

What makes a proton shake quickly?

Color wavelength frequency

n

(102)

What makes a proton shake slowly?

Color wavelength frequency