d. the atom unit 3 2010 by ChemistryAdventure

The Atom Unit 4

How do we know that the world is made out of atoms? A historical approach. Page 1 Unit 4: the atom

The Atom Unit 4 Our Essential Question: How do we know that Atoms Exist? All year we will be trying to answer a simple question: What is everything made out of? Right now, we can say that everything is composed of matter. True, but it doesnâ&#x20AC;&#x2122;t tell us much. We also have heard that matter is composed of individual atoms. Butâ&#x20AC;Śhow do we know that is true? People have been asking themselves that question ever since Democritus popularized the idea 2400 years ago. We will be asking ourselves the same question this week: How do we know that atoms exist? To help answer this question we will take a look at how this question has been answered historically up to 1907, at which point most scientists believed the evidence was overwhelming. We will also work together on a project to find detailed historical evidence. Here is the tentative plan: Day 1: Lesson: History of the atom presentation. Lab: Seeing the atom web-based project day 1 of 2 Homework: History of the atom worksheet Day 2: Lesson: The atom Lab: Seeing the atom web-based project day 2 of 2. Homework: Day 3: Lesson: Percent composition, average atomic mass, and isotopic abundance Lab: Rehearse Seeing the Atom presentations Homework Day 4: Lesson: AtomTest Review Lab: Seeing the Atom Presentations Homework: Review for test Day 5: Atom Test Introduction to Unit 5: Electrons.

The atom: Early Ideas Symbol

Inventor

Idea, source

The atom Democritus 400 BC

No written record Earth, air, fire, and water

Aristotle

400 BC

Greek writings

Split the atom Ghazali

The Chemistry of Happiness

1000 AD

Their Evidence:

Nothing! 3 Unit 4: the atom

First Evidence for the atom

Mass is conserved Lavoisier

Mg + S

MgS

24 g 32 g

56 g

Atoms combine in small whole numbers

Dalton

â&#x20AC;˘ Mass percent ws

Thomson’s 1897 experiment: Are you convinced?

1. Bends “light”

2. Moves a propeller

3. m/c indicates 1000X smaller than a hydrogen atom • Proposes: The Electron • Thomson 5

Where are the electrons? Rutherfordâ&#x20AC;&#x2122;s 1907 Gold Foil Experiment Conclusion:

nucleus

Most particles go right through the ultra-thin Gold foil.

Rutherford

1. Electrons are outside the nucleus 2. The atom is mostly space But..No idea of electron organization 6 Unit 4: the atom

Is the world made out of atoms? Chronological Evidence

History of the atom from Democritus to Mikhailovskij

Mikhailovskij field emission electron microscopy (FEEM) Atomic image including orbitals

Democritus Atomos Evidence: nothing

Rutherford 1790 jimmy neutron

Aristotle Earth, Air, Fire, Water: Phases!

Ghazali Alchemist We can split the atom

Thomson Electrons Plum pudding Dalton: bonds Atoms combine in small whole numbers

Lavoisier Balance: Indestructible Conservation of mass

Atomic Bookkeeping: p+, no, and eTerm

means

Atomic #

# p+; blue #

2He

#p+

Mass #

#no

example Fix 32S:

16S 2

+ o 2He or He-5 has __ p , __n

isotope

#no varies

He-4 and He-5 are isotopes

ion

#p+ = #e-

11 +, 10 Na+ has __p __e-

cation

#p+ > #e-

Ca2+ 20 p+, 18 e- is____

anion

#p+

p+,

Average Atomic mass

Band of Stability

#e-

â&#x20AC;&#x153;red #â&#x20AC;? If #no/#p+ > 1.5 run!

3N is____

98.9% C-12 a.a.m. = (0.989)(12) 1.1 % C-13 + (0.011)(13) = 12.011

U-238: 144/92 = 1.56 = run!

isoelectronic F- and Neon both have ___ 10 electrons: They are _____________. 8

Determination of average atomic mass • Element X has 2 isotopes: • • • •

Isotope a 10 protons, 10 neutrons Abundance: 40%

• Isotope b has 10 protons 11 neutrons • Abundance: 60%

What is the average atomic mass of Element X?

• Solution: • (0.4)(20) + (0.6)(21) =

• 20.6 amu • a.a.m = sum of (abundance)(mass #) 9

You try one: Element Guryanovium (Gu) • P N Mass? • 15 15 • 15 17

abundance 66% 34%

Average Atomic

• 30.68 amu How many neutrons is too many?:

The “Band of Stability” • In general •

n/p >1.5 = unstable = radioactive • All elements >82

mikhailovskij

Rutherford

Thomson

Dalton

Lavoisier

Ghazali Aristotle

democritus

History of the atom worksheet

ws 4.1

Complete this worksheet after listening to the presentation on the history of the atom from 400 BC to 1907 AD. Refer to the notes on your slides if you need to for each question. 1. What is the essential question for this course? 2. What is the essential question for this unit? 3. What would you need to see, know, or observe to become convinced that atoms exist?

4. By now you have seen a presentation on some ideas and experiments concerning the atom from about 2400 BC to 1907. Fill in the table below to summarize the work and significance of some of the key players. name

Democritus

Aristotle

Ghazali

Lavoisier

Dalton

Thomson

Rutherford

Symbol

Contribution

5. How is Daltons model of the atom different from that of Democritus?

6. Draw a picture of the Cathode Ray tube used by Thomson, identifying each component. Show 2 experiments that indicate the green light in the tube is in fact not light.

7. Light is a form of electromagnetic energy and has no mass. Compare that to the green light in the cathode ray tube.

8. How might the gold foil experiment suggest the shape of an atom?

9. How big is an electron compared to a hydrogen atom?

10. Draw a figure and explain Rutherfordâ&#x20AC;&#x2122;s Gold foil experiment:

11. Lavoisierâ&#x20AC;&#x2122;s experiments indicated that mass is never lost when chemical reactions occur. Daltons experiments suggested that elements come in different sizes, and they combine in simple ratios. Thomson showed there is something smaller than hydrogen, and Rutherford showed that there is a lot of empty space in matter. Based on those experiments and a hunch that the atom may resemble our solar system, the early 20th century model of the atom is the Jimmy Neutron symbol. To understand the atom is to understand all matter on its most basic level. What did they still NOT know about the atom at this point? List as many things as you can.

Atomic Bookkeeping Worksheet

ws 4.2

Atomic Particles, Atomic Number, Mass Number, Ions, and Isotopes Here are some quick facts to help you keep track of the names and numbers associated with the atom:

Protons are in the nucleus, each has a +1 charge, and identifies the element. Neutrons are in the nucleus, each has no charge, and determines the isotope. Electrons are outside the nucleus, each has a -1 charge, and determines the reactivity. Atomic Number is the number of protons. Mass number is the number of protons + neutrons Average atomic mass is the averaged mass for a mixture of isotopes An ion has either more or less electrons than protons, so it is charged. Isotopes vary only in the number of neutrons for an element. 1. Pick an element, any element. My element has the symbol _______, which stands for ____________. It has ______ protons, and when uncharged also has _________ electrons. The average atomic mass of this element is ________ atomic mass units. If it has one extra electron, this would give it a _____ charge. If one atom had two more neutrons than protons, the mass number would be ________ atomic mass units. 2. Fill in the blanks below: ____________average atomic mass ____________chemical symbol ____________chemical name ____________atomic number

Hydrogen 1 H 1.008

3. Complete the following table: Element O (oxygen) Zn (zinc)3+ Sn (tin)Fe (iron)3+ C (carbon) H (hydrogen)+ Sg (seaborgium)

Number of protons 8

Number of electrons

4 What is an isotope? 5. What is the difference between mass number and atomic number?

Average atomic mass 15.999

1. Complete the following table:

Atomic mass/average atomic mass worksheet Element O (oxygen) Zn (zinc) Sn (tin) Fe (iron) C (carbon) H-(hydride) Note the negative sign! Sg (seaborgium)

Number of protons 8

Number of electrons 8

Number of neutrons 9 37

Mass number 17 118

30 14 0

266

2. Mass number and atomic number are easy to confuse. To determine atomic number one only needs to know the number of _____________, whereas the mass number also includes the number of_____________. 3. Chlorine has two naturally occurring isotopes, Cl-35 and Cl-37. The lighter isotope is _____ which contains _____ protons and _____ neutrons. The heavier isotope is _______ with _____ protons and _____ neutrons. 4. Here is a problem that is solved for you. As you read the problem, imagine how you could solve it without a calculator, then see how it is done, and apply the solution to #5. An imaginary element X has two isotopes, one with a mass of 20 atomic mass units (amu), and the other with a mass of 22 amu. They both occur with equal (50%) abundance. What is the average atomic mass of X? Solution: (0.5)(20) + (0.5)(22) = 21 a.m.u. 5. What would the atomic mass of element X above be if the abundances of X-20 was 25%, and the abundance of X-22 was 75%? Solution (fill in the missing numbers: ( )( ) +( )( ) = _____ a.m.u. 6. Silver has 2 isotopes. One has a mass of 106.905 amu (52%) and the other has a mass of 108.905 amu (48%). What is the average atomic mass of this isotopic mixture of silver?

Isotopes, ions, atomic mass, and average atomic mass worksheet

ws4.3

The number of protons, electrons, and neutrons is usually symbolized in an element box in the following manner: For example: 235 41 Mass number

(p + + n 0) 24

Charge (p + + e -)

Na+

F-

9 protons 10 neutrons 10 electrons

atomic number (p + )

20 protons 21 neutrons 18 electrons

92 protons 143 neutrons 92 electrons

Once the number of each atomic particle is known, it is an easy matter to identify isotopes (atoms that vary only in the number of neutrons) or ions (atoms that do not have the same number of protons and electrons). 1. Fill in the blanks

___protons ___ neutrons ___electrons

238

___protons ___protons ___ neutrons ___ neutrons ___electrons ___electrons

238

___protons ___ neutrons ___electrons

___protons ___protons ___ neutrons ___ neutrons ___electrons ___electrons

7 protons 9 neutrons 8 electrons

105 protons 8 protons 132 neutrons 8 neutrons 106 electrons 8electrons

2. Which pairs of elements are isotopes?

3. Which elements are ions? 4. Fill in the boxes below.

1 protons 0 neutrons 1 electron

23 protons 24 neutrons 22 electrons

5 protons 6 neutrons 8 electrons

5. Are the following pairs of compounds isotopes, ions, or different elements? Also, provide the full atomic symbol for each substance Example: a. Substance 1: 10 protons, 10 neutrons, 10 electrons: b. substance 1: 10 protons, 11 neutrons, 10 electrons Relationship: isotopes

c. Substance 1: 10 protons, 10 neutrons, 10 electrons d. substance 1: 9 protons, 10 neutrons, 10 electrons Relationship:________________ e. Substance 1: 10 protons, 10 neutrons, 11 electrons f. substance 1: 10 protons, 10 neutrons, 10 electrons Relationship:________________ 6. Determine the average atomic mass for the following imaginary elements, using the first question as an example.

Solved Example. Isotope 1: 4 protons, 4 neutrons. Abundance : 91% Isotope 2: 4 protons, 5 neutrons. Abundance : 9% Average atomic mass = sum of (abundances)(mass number) = (0.91)(8 amu) + (0.09)(9 amu) = 8.09 amu a. Isotope 1: 14 protons, 14 neutrons. Abundance: 62% Isotope 2: 14 protons, 16 neutrons. Abundance : 38% Average atomic mass =

b. isotope 1: 94 protons,104 neutrons. Abundance : 52% Isotope 2: 94 protons, 112 neutrons. Abundance: 48% Average atomic mass =

c. Isotope 1: 24 protons, 24 neutrons. Abundance : 40% Isotope 2: 24 protons, 25 neutrons. Abundance : 39% Isotope 3 : 24 protons, 28 neutrons abundance = 21%

3. Level One Only: Boron has two naturally occurring isotopes. Boron -10 (abundance = 19.8%; mass = 10.013 amu) and another isotope (abundance 80.2%). The average atomic mass of boron is 10.811 amu. What is the mass of the other isotope?

How to ace the Atom unit

Howtoaceitunit4

In this our fourth unit, we explored the atom. Our goal was to answer the question: How do we know that atoms exist? We began with a chronological study, starting with the ideas of Democritus, and ending with the discovery of the nucleus by Rutherford. We also considered what it would take to convince us that atoms in fact do exist, and we found evidence that atoms have been individually observed and moved. We then focused on the three primary subatomic particles. We considered their location, mass and charge, and this led to an understanding of atomic number, mass number, and average atomic mass. Finally, we applied this to isotopes, and finished with the band of stability- the ratio of protons to neutrons for a stable atomic nucleus. In our next unit we will focus on the subatomic particle that determines the chemical behavior of each element: the electron. To ace this unit you should review the powerpoint slides, the atom worksheets, and this study guide. You should also review the results of our Seeing the Atom project. Here are some quick questions on each topic we covered. 1. The history of the discovery of the atom: a. Aristotle and his four â&#x20AC;&#x153;elementsâ&#x20AC;? b. Democritus: symbol and what he got right c. Paracelsus: Symbol and contribution d. Lavoisier: Symbol, contribution, and his untimely end e. Dalton: symbol and his major contribution f. Thomson: symbol, what he discovered, device he used, evidence . g. Rutherford: symbol, and his key experiment 2. The 3 subatomic particles, their mass in atomic mass units (amu), and charges

3. Atomic number

Example: What are the atomic numbers for each element in baking soda, NaHCO3? Why can Magnesium never have 13 protons?

4. Mass number

Example: What is the mass number of an oxygen atom that has 8 neutrons and 9 protons?

5. Average atomic mass formula

Example: Element X has two isotopes. One has an abundance of 63% and an atomic mass of 10 a.m.u. The other has an abundance of 37% and an atomic mass of 15 a.m.u. What is the average atomic mass of element X?

6. Isotopes- definition (watch out for cases that are different elements, not different isotopes)

Example: How many protons and neutrons are present in an atom of Cs-111?

7. Ions- know how to calculate charge on an atom

Example: How many protons, neutrons, and electrons are present in an atom of C-13?

Example: Draw element boxes that show an example of a fluoride monoanion (-1), and a calcium dication (+2).

8. Nuclear stability

Example: Circle the stable isotopes: U-238 Po-208 C-14 9. Chemical symbols for elements 1-20

What are the symbols for

hydrogen, helium, lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, neon, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, argon, potassium, and calcium,? 10. How do you know that atoms exist? Provide quantitative evidence in addition to imaging. Be sure to review the Seeing the Atom Presentations from each of you. Good luck on the test.

How to ace the Atom unit KEY

Howtoaceitunit4

In this our fourth unit, we explored the atom. Our goal was to answer the question: How do we know that atoms exist? We began with a chronological study, starting with the ideas of Democritus, and ending with the discovery of the nucleus by Rutherford. We also considered what it would take to convince us that atoms in fact do exist, and we found evidence that atoms have been individually observed and moved. We then focused on the three primary subatomic particles. We considered their location, mass and charge, and this led to an understanding of atomic number, mass number, and average atomic mass. Finally, we applied this to isotopes, and finished with the band of stability- the ratio of protons to neutrons for a stable atomic nucleus. In our next unit we will focus on the subatomic particle that determines the chemical behavior of each element: the electron. To ace this unit you should review the powerpoint slides, the atom worksheets, and this study guide. You should also review the results of our Seeing the Atom project. Here are some quick questions on each topic we covered. 1. The history of the discovery of the atom: a. Aristotle and his four “elements” cross, AFEW b. Democritus: symbol and what he got right Ball; the world is made out of atoms c. Ghazali: Symbol and contribution split ball; suggested we could split the atom d. Lavoisier: Symbol, contribution, and his untimely end balance; atoms may be indestructible; guillotined e. Dalton: symbol and his major contribution barrel o’monkeys; bonds f. Thomson: symbol, what he discovered, device he used, evidence .plum pudding; electrons; cathode ray tube; magnet, propeller, and mass to charge ratio g. Rutherford: symbol, and his key experiment james Isaac neutron; gold foil 2. The 3 subatomic particles, their charges P+, N0, E3. Atomic number

Example: What are the atomic numbers for each element in baking soda, NaHCO3? Na 11, H1, C6, O8 Why can Magnesium never have 13 protons? Yo that’s aluminum bro

4. Mass number

Example: What is the mass number of an oxygen atom that has 8 neutrons and 9 protons?

17 5. Average atomic mass formula

6. Isotopes- definition (watch out for cases that are different elements, not different isotopes)

Example: How many protons and neutrons are present in an atom of Cs-111?

55P,, 56N 7. Ions- know how to calculate charge on an atom

Example: How many protons, neutrons, and electrons are present in an atom of C-13? 6P, 7N, 6e Example: Draw element boxes that show an example of a fluoride monoanion (-1), and a calcium dication (+2). Heres the list: F- has 9P, 10e, average atomic mass of 18.9 amu Ca +2 has 20 P, 18 e, and an average atomic mass of 40.0 amu

8. Nuclear stability

Example: Circle the stable isotopes: U-238 Po-208 C-14 9. Chemical symbols for elements 1-20

What are the symbols for Refer to periodic table hydrogen, helium, lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, neon, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, argon, potassium, and calcium,?

10. How do you know that atoms exist? Provide quantitative evidence in addition to imaging. Please be prepared to write a persuasive essay. Be sure to review the Seeing the Atom Presentations from each of you. Good luck on the test.

Supplemental Next year

5. Are the following pairs of compounds isotopes, ions, or different elements? Also, provide the charge and the full atomic symbol for each substance. Use the first two rows as an example. Atom

Protons

Neutrons

Electrons

charge

Symbol

0 0

10 20 10

Relationship

Ne isotopes

6. Determine the average atomic mass for the following imaginary elements, using the first question as an example. Solved Example. Isotope 1: 4 protons, 4 neutrons. Abundance : 91% Isotope 2: 4 protons, 5 neutrons. Abundance : 9% Average atomic mass = sum of (abundances)(mass number) = (0.91)(8 amu) + (0.09)(9 amu) = 8.09 amu

Name________________________________________________________________ Period______________ Introduction to the Atom ws 4.0 The Cartoon Guide to Chemistry Chapter 1: Hidden Ingredients Worksheet I wonder about atoms. How do we know that the world is, as the experts say, made out of atoms? Read the animated chronological guide with a skeptical mind, then answer the questions below. 1. What was very likely the first chemical reaction to impress our ancestors?

2. How could copper be isolated from a rock? 3. The atomists believed that matter was ultimately composed of __________, Heraclitus proposed that all matter was made out of _________, and Aristotle suggested there are in fact only four elements: ___________, ____________, ____________, and _____________. Thinking about it, the atomists seem to have somehow got it right, and Aristotle was way off- those four elements are really ______________________________________. And it can be argued that Heraclitus may be right after all…how might all elements be created by “fire”?

4. In the middle ages, the ________________ became obsessed with the synthesis (creation) of gold. They failed. 5. Gases baffled scientists until methods to isolate them were developed. Using the contributions of Joseph Priestly, draw a method for isolating a GAS from a chemical reaction.

6. What was it that Priestly breathed that made him feel “light and easy” , and what was the chemical reaction that created it ?

7. I just watched “The Golden Compass” where they told of a mythical device known as an Elythiometer: a device that tells the truth. Antoine Lavoisier, it can be argued, used the worlds first Elythiometer. What was it?

8. John Dalton suggested that atoms combine in small whole numbers to form ___________.

9. Once it was realized that atoms were of different types, and they got incrementally larger, and some were more reactive than others, patterns began to emerge. Mendeleev was one of the first to sort it out when he created a crude ___________ _________. 10. What are atoms made out of?

Name_____________________________________________ Period ___________________

Matter Test Activity 10 Points Chomatograph a candy coating and tape your chromatogram to this paper. Please label 1. 2. 3. 4. 5.

The baseline The solvent front The estimated Rf value of any visible substances What is the stationary phase used in this purification method? What mobile phase did you choose to use?

The atom. Evidence-based Ideas: Symbol Inventor Concept Mass is conserved Lavoisier

Dalton

Thomson

Rutherford

Atoms combine in small whole numbers Electron

Nucleus

26 Unit 4: the atom

The atom: 400 BC-1907

â&#x20AC;˘ Brief video summary:1:00-1:57 27

How do we know that the world is made out of atoms? List 2 types of evidence that would convince you personally that atoms do in fact exist: 1. 2. A brief cyclical atom timeline

Democritus 400 BC ball

Mikhailovskij 2009 picture

Aristotle 350 BC cross

Rutherford 1790 jimmy neutron

Thomson 1905 plum pudding

Ghazali 1100 split ball

Dalton 1820 earrings

Lavoisier 1790 balance

Seeing the Atom Translation Project

Goal: To Translate Igor Mikhailovskij’s Atom Image paper from english to plain english, rewriting so it is understandable to a non-scientist. Introduction: On October 7, 2009, a team of scientists led by Igor Mikhailovskij published the first detailed image of a carbon atom. This paper has been since highlighted on the web, and in magazines such as Scientific American. This paper is complex and is loaded with technical jargon. Our goal is to rewrite it so that a non-scientist could make sense of it. Procedure: 1. Each team will be assigned a section of the paper. Read it and answer at least 5 questions each on topics you don’t understand. 2. Using an online editable version, edit your section to make it readable by a non-scientist. 1. Simplify any technical jargon. For example, the first sentence reads “Carbon atomic chains have remarkably high stability and failure current density, and are therefore especially promising in all-carbon molecular electronics.” This could be simplified to say ”Single chains of carbon atoms may some day be used in electronics, since they are durable and conduct electricity well. “ 2. Look up each reference and summarize it so the reader doesn’t have to bother looking it up. Include the original reference, but if you find at least an abstract online add the website. 3. For areas that are just too complex, consider a simplifying sentence, and include all the technical stuff as an endnote. For example, at one point the paper reads “… Using these expressions, the calculation yielded the following expression for the minimal diameter of resolved emission spots in FEEM images of free-standing linear nanoobjects:[complex formula follows]…” This might be written as “For those interested, calculations are available that

Seeing the Atom Translation Project 50 Points Goal: To complete our historical study of the atom we will translate Igor Mikhailovskijâ&#x20AC;&#x2122;s Atom Image paper from English to Plain English, rewriting so it is understandable to a non-scientist.

Introduction: On October 7, 2009, a team of scientists led by Igor Mikhailovskij published the first detailed image of a carbon atom. This paper has been since highlighted on the web, and in magazines such as Scientific American. This paper is complex and is loaded with technical jargon. Our goal is to rewrite it so that a non-scientist could make sense of it. Scoring Guide (10 points each) 1. All technical jargon and complex wording has been replaced with words commonly used by nonscientists without omitting key concepts in the paper. Ridiculously complex material is endnoted. An example is given below. 2. References are still included, and are summarized so the reader may not have to look them up. If a website is available, it is included. 3. The paper is grammatically clear and does not have typographical errors 4. The paper is interesting to read, and is not boring. 5. Names and section number are at the top of the page. The entire section is RED. A hard copy is given to Dr B on the due date, and an electronic copy is sent to the class dropbox This project is due on Tuesday, November 9, 2010. 10% off for each late day. Please see the back side of this paper for how to deal with ridiculously complex material.

Seein the Atom Scoring Guide (10 points each) 1. All technical jargon and complex wording has been replaced with words commonly used by nonscientists without omitting key concepts in the paper. Ridiculously complex material is endnoted. An example is given below. 2. References are still included, and are summarized so the reader may not have to look them up. If a website is available, it is included. 3. The paper is grammatically clear and does not have typographical errors 4. The paper is interesting to read, and is not boring. 5. Names and section number are at the top of the page. The entire section is RED. A hard copy is given to Dr B on the due date, and an electronic copy is sent to the class dropbox.

How to endnote ridiculously complex material in the Mikhailovskij paper. If you come across some technobabble that just doesn’t belong , consider “endnoting” it. For example there is a section with formulas on the “compression factor”. Here is how one student endnoted it.

Before: Within the framework of this approximation, the compression factor is given by f=

(r0/L)1/2,

After:

(1)

where L is the total distance of the apex of the hemisphere from the paraboloid surface (L=l+p0) and is a numerical constant which is almost independent of configurations of chains and supporting tips and has an approximate value of 1.145.17 The apex field-enhancement factor for the chain on a paraboloid model is given by -=1.05(2+L/p0)0.99. The field F at the end of the chain anchored at the apex of a paraboloidal tip can be shown to be F=2-V/r0 ln(2R/r0). Using these expressions, the calculation yielded the following expression for the minimal diameter of resolved emission spots in FEEM images of free-standing linear nanoobjects: −1/4 eme 0 = (21 p0)1/2[-LF ln(2R/r0)]. (2)

The microscopic image of a carbon atom is compressed, just like any digital image. Mathematical details are available.17 (And endnote 17 contains all the formulas, definition of terms in the formula, etc.)

Can we see the atom?

Can we see the atom? Imaging the atomic orbitals of carbon atomic chains with field-emission electron microscopy I. M. Mikhailovskij,* E. V. Sadanov, T. I. Mazilova, V. A. Ksenofontov, and O. A. Velicodnaja Department of Low Temperatures and Condensed State, National Scientific Center, Kharkov Institute for Physics and Technology, Academicheskaja, 1, Kharkov 61108, Ukraine (Received 17 July 2009; revised manuscript received 2 September 2009; published 7 October 2009) A recently developed high-field technique of atomic chains preparation has made it possible to attain the ultrahigh resolution of field-emission electron microscopy (FEEM), which can be used to direct imaging the intraatomic electronic structure. By applying cryogenic FEEM, we are able to resolve the spatial configuration of atomic orbitals, which correspond to quantized states of the end atom in free-standing carbon atomic chains. Knowledge of the intra-atomic structure will make it possible to visualize generic aspects of quantum mechanics and also lead to approaches for a wide range of nanotechnological applications. DOI: 10.1103/PhysRevB.80.165404 PACS number(s): 61.05.-a, 68.37.Vj, 81.07.Vb

Dear Professor Mikhailovskij I am a US high school teacher who would like to request an image of you for our atom unit. We are studying the history of research on the atom from Democritus to the present, and we would like to conclude with your recent contributions (1). Sincerely, Dr. Harry Brielmann High School Chemistry Teacher Guilford High School Guilford CT USA http://chemistryadventure.com

1. "Imaging the atomic orbitals of carbon atomic chains with field-emission electron microscopy," by I. M. Mikhailovskij, E. V. Sadanov, T. I. Mazilova, V. A. Ksenofontov and O. A. Velicodnaja, in PHYSICAL REVIEW B, Vol. 80, NO. 16; October 2009

Dear Dr. Brielmann, Many thanks for your letter. In Att. you can find of Fieil-electron images of carbon atom from our paper in Phys. Rev. With kind regards, Igor Mikhailovskij.

Professor Mikhailovskij Thank you for your FEEM images. Perhaps I wasn't clear. I am interested in a picture of you personally for inclusion in our history of the atom. I have images of Democritus, Aristotle, Thomson, Rutherford, and others; your image will be our most recent. All of my high school students will read your Phisical Review B 2009 paper. Attached is the powerpoint file. The image is not you (my apologies). Sincerely, Dr. Harry Brielmann

Dear Dr. Brielmann, Many thanks for your letter and PowerPoint file. In Att. you can find my photos at various times and image of our team, coathors of the paper in Phys. Rev. With gratitude and confusion, Igor Mikhailovskij.

Dear Dr. Brielmann, I am coauthor of Igor Mikhailovskij in the paper "Imaging the atomic orbitals of carbon atomic chains with field-emission electron microscopy," in Phys. Rev. We were sincerely glad to see our image of carbon atom in your presentation among great achievements. Would you be so kind to send me your powerpoint file with images of Democritus,â&#x20AC;Ś and our leader. Sincerely, Tatjana Mazilova, Dr. Sci.

Dr. MazilovaAttached is one slide from our current chemistry class unit: History of the Atom: From Democritus to Mikhailovskij. You can also watch and listen to the screencast at http://www.screencast.com/t/ZRCngzhnFc. I hope you enjoy it. Our students (14-15 years old) are currently working on a project where they "translate" your recent paper from english to "simple english", the goal being to make it understandable to a non-scientist. Would it be OK to ask you a few questions? There are many aspects of this work that are not clear to them (or me!). This would help us enormously. Sincerely, Dr Harry Brielmann Guilford High School Guilford CT USA

Is the world made out of atoms? Chronological Evidence

History of the atom from Democritus to Mikhailovskij

Mikhailovskij field emission electron microscopy (FEEM) Atomic image including orbitals

Democritus Atomos Evidence: nothing

Rutherford 1790 jimmy neutron

Aristotle Earth, Air, Fire, Water: Phases!

Ghazali Alchemist We can split the atom

Thomson Electrons Plum pudding Dalton: bonds Atoms combine in small whole numbers

Lavoisier Balance: Indestructible Conservation of mass

Dear Harry, Many thanks for your slide. We are waiting for your qustions and will try answer... Sincerely, Tatjana.

How to Ace the Atom Test: Additional Topics (L1, honors) After reading the atom packet, watching the slide show, completing the worksheets, and completing the â&#x20AC;&#x153;seeing the atomâ&#x20AC;? project, you now should have a good idea of the basic structure of the atom and its three subatomic particles. Here are some additional questions to ponder. A key is available, but not for all questions. Like all good scientists, some you will have to research on your own. 1.

About how big is an atom in meters?

What is the most powerful plain old optical microscope?

What was Democritus' evidence for his proposal that atoms exist?

Based on what you have learned, what would be the Aristotle's Fifth Element?

When did humans accomplish what Ghazali said was possible?

What might Lavoisier have concluded if his balance was inaccurate?

Provide five elements that support Daltons bonding hypothesis

What is in all of that space that Rutherford discovered?

What is an alpha particle?

10. What would an atom look like if Rutherford found that only 1% of his alpha particles made it through the gold foil? 11. What would it mean if all of the alpha particles were turned into ordinary uncharged helium atoms? 12. What would have happened if Rutherford used electrons instead of alpha particles? 13. Rutherford particularly liked the fact that alpha particles were positively charged. Why?

14. The big wheel scientists of the day such as Einstein and Mosely were very skeptical of Rutherfords model. Suggest two possible shortcomings of Rutherford's model. 15. Where is Kharkov? 16. What country is Kharkov in? What form of government is Kharkov subject to? 17. How do you spell Igor’s last name? 18. What does FEEM stand for? 19. Draw a diagram of a FEEM. Include a sample, a field-modified sample, the tip of the FEEM, and the phosphor screen

20. How does a phosphor screen work? 21. Igor M and his team refer to their sample at “carbon atomic chains” Do you think there are chemical bonds in this chain or not? Why? 22. How is it that their graphite sample gets pulled up into a atomic chain? 23. The FEEM image only shows one of the three subatomic particles. Which one? 24. Tell me about Kharkov in the early 1940’s. 25. What would Rutherford have thought of Igor M.’s result? 26. What would Thomson have concluded if the green “light” in his cathode ray tube was not bent by a magnet, or moved by a propeller? 27. How do we know that atoms exist?

How to Ace the Atom Test: Additional Topics (L1, honors) KEY After reading the atom packet, watching the slide show, completing the worksheets, and completing the “seeing the atom” project, you now should have a good idea of the basic structure of the atom and its three subatomic particles. Here are some additional questions to ponder. A key is available, but not for all questions. Like all good scientists, some you will have to research on your own. 1. About how big is an atom in meters? about a billionth of a meter (a nanometer) 2. What is the most powerful plain old optical microscope? please look this one up. 3. What was Democritus' evidence for his proposal that atoms exist? nothing , zip, nada 4. Based on what you have learned, what would be the Aristotle's Fifth Element? liquid crystals. (in the Bruce Willis movie it was love) 5. When did humans accomplish what Ghazali said was possible? 1944 6. What might Lavoisier have concluded if his balance was inaccurate? matter is not indestructible, and can disappear, or appear …(can it?) 7. Provide five elements that support Daltons bonding hypothesis H1 O2 N3 C4…the halogens (F, Cl, Br, I) also form one bond. 8. What is in all of that space that Rutherford discovered? nothing, zip, nada 9. What is an alpha particle? a helium nucleus (He2+) 10. What would an atom look like if Rutherford found that only 1% of his alpha particles made it through the gold foil? Please solve this on your own. 11. What would it mean if all of the alpha particles were turned into ordinary uncharged helium atoms? Please solve this on your own. (tough one: honors only) 12. What would have happened if Rutherford used electrons instead of alpha particles? Please solve this on your own. 13. Rutherford particularly liked the fact that alpha particles were positively charged. Why? Because they would not stick to the nucleus- they would be repulsed.

14. The big wheel scientists of the day such as Einstein and Mosely were very skeptical of Rutherfords model. Suggest two possible shortcomings of Rutherford's model. He has electrons separated from the nucleus, even though they are attracted to each other He has no clue where the electrons are in all that space; the model says nothing about chemistry. 15. Where is Kharkov? Please solve this on your own 16. What country is Kharkov in? What form of government is Kharkov subject to? Ukraine, democratic 17. How do you spell Igor’s last name? Mikhailovskij 18. What does FEEM stand for? Field emission electron microscope 19. Draw a diagram of a FEEM. Include a sample, a field-modified sample (how it changes as it is attracted to the tip), the tip of the FEEM, and the phosphor screen Please solve this on your own; refer to the figures in the Mikhailovskij paper. 20. How does a phosphor screen work? Please solve this on your own 21. Igor M and his team refer to their sample as “carbon atomic chains” Do you think there are chemical bonds in this chain or not? Why? II think not…a carbon chain cannot be drawn without other atoms at the tips 22. How is it that their graphite sample gets pulled up into a atomic chain? Tough one: honors only. 23. The FEEM image only shows one of the three subatomic particles. Which one? electrons 24. Tell me about Kharkov in the early 1940’s. From 41-43 it was no-mans land- violent battles of WWII. After, reconstruction. 25. What would Rutherford have thought of Igor M.’s result? It is consistent with his model, and reveals further details. 26. What would Thomson have concluded if the green “light” in his cathode ray tube was not bent by a magnet, or moved by a propeller? It’s just green light. 27. How do we know that atoms exist? Please be prepared to answer this in detail.