atoms, the building blocks of matter - niagara.k12.wi.us 3 notes .pdf · john dalton: english...

notes for chapter 3_2017.notebook

1

October 26, 2017

Oct 1211:08 PM

Atoms, the Building Blocks of Matter

1


2

October 26, 2017

Oct 223:40 PM

Learning objective:The learner will explain :• explain the law of conservation of mass• law of definite proportions• law of multiple proportion

summarize:• Dalton's atomic theory• and explain how this relates to the above laws


3

October 26, 2017

Oct 198:09 AM

atoms: Smallest unit of an element that retains all of the properties of that element

electron: A negatively charged, subatomic particle located outside the nucleus of an atom. (in electron cloud)

nucleus:

neutron: Neutrally charged subatomic particle in the nucleus of an atom

proton: Positively charged subatomic particle in the nucleus of an atom

center region of an atom that contains the neutrons and protons


4

October 26, 2017

Oct 199:27 AM

atomic #

ion: an atom that has lost or gained 1 or more electrons

Isotope: are atoms of the same element with different #'s of neutrons

Gives the position of an element on the periodic table of elements and the number of protons

atomic mass

number:# of protons +neutrons in the nucleus


5

October 26, 2017

Oct 289:43 AM

Atom → Greek philosopher: DemocritusAtomus: indivisible

Aristotle → no, matter is a continuous

sheet: "Hoyle"

Early ideas :


6

October 26, 2017

Oct 198:27 AM

2. All atoms of same element are identical in size, mass, and chemical properties

3. Atoms cannot be subdivided, created, or destroyed

John Dalton: English Chemist in the 1700'sDalton's Atomic Theory

1. All matter is made of very small particles called atoms

4. Atoms combine in simple, whole number ratios to form compounds5. In chemical reactions, atoms are combined, separated, or rearranged to form new substances


7

October 26, 2017

Mar 197:45 AM

Note questionpageNotes

Where Does Modern Atomic Theory differ from Dalton's Atomic Theory?

1. WE now know that elements have atoms with different ______________ which means the number

of _______ differs.

2. We now know that atoms have ____ _________

________________.

massesneutrons

sub atomicparticles


8

October 26, 2017

Oct 127:14 PM

Early Research in Subatomic Particles

The first subatomic particle discoveredwere electrons in cathode ray tube experiments

Low pressure

gases

enclosed in

tube

discover,


9

October 26, 2017

Oct 127:57 PM

• Thomson conducted a series of experiments with cathode rays and cathode ray tubes • leading him to the discovery of electrons and subatomic

particles. Thomson used the cathode ray tube and the results of

experiments conducted by Perin in three different experiments

http://www.aip.org/history/electron/


10

October 26, 2017

Oct 128:16 PM

He found 1. when the rays entered the slit in the cylinders, the electrometer measured a large amount of negative charge.

2.The electrometer did not register much electric charge if the rays were bent so they would not enter the slit.

His conclusion: the negative charge and the cathode rays must somehow be connected: you cannot separate the charge from the rays.


11

October 26, 2017

Oct 128:14 PM

Rays from the cathode (C) pass through a slit in the anode (A) and through a slit in a grounded metal plug (B). An electrical voltage is established between aluminum plates (D and E), and a scale pasted on the outside of the end of the tube measures the deflection of the rays.

Thomson's apparatus in the second experiment.

conclusion: [cathode rays] are charges of negative electricity carried by particles of matter


12

October 26, 2017

Oct 128:31 PM

Robert Milikan

Discovered the charge on a single electron through his famous oil drop experiment.using this and the ratio of the charge to mass, the massof an electron was calculated to be 1/1837th that of a hydrogen atom.


13

October 26, 2017

Oct 128:34 PM

• The original experiment was performed in 1909• balanced the downward gravitational force and the upward electrical forces of charged oil droplets suspended between two metal plates. • The mass of the droplets and the density of the oil was known

How the Oil Drop Experiment Worked

http://www.youtube.com/watch?NR=1&v=XMfYHag7Liw&feature=endscreen


14

October 26, 2017

Oct 1210:42 AM

• measured radii of the oil drops. • the electric field that held the droplets suspended was measured • The value for the charge was calculated for many droplets. • The values were multiples of the value of a charge of a single electron. Millikan and Fletcher calculated the charge of an electron :

1.5924(17)×10−19 C (coulombs). Their value was within one percent of the currently accepted value for the charge of an electron: 1.602176487(40)×10−19 C


15

October 26, 2017

Oct 1210:18 PM

Other Questions:1. Atoms are electrically neutral

*since electrons are negative, what balances that negative charge?2. Atoms have measurable mass

*electrons are not anywhere near the mass of the atom-what gives the atom its mass?


16

October 26, 2017

Oct 1210:48 PM

Thomson's model, based on these resultsis known as the "plum pudding" model.The atom, he hypothesized, is a sphere of positive charge to counter the electrons. The electrons were free to move around in this charge as though it were a kind of liquid.

http://www.ukastronomy.com/atom.htm

http://www.uk-astronomy.com/atom.htm


17

October 26, 2017

Oct 1210:45 PM

Rutherford and associates did investigations with radioactive particles and gold foil.

http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/ruther14.swf


18

October 26, 2017

Oct 1210:48 PM

• Considered this phenomenon for 2 years • finally concluded that the alpha particles• must have encountered a very densely packed, positive charge • very small or more would have deflected. • He called this the nucleus


19

October 26, 2017

Oct 243:35 PM


20

October 26, 2017

Oct 1210:48 PM

Composition of the nucleus

Must account for the positive chargeMust account for the high mass

We know: protons account for the positive charge Neutrons account for the mass


21

October 26, 2017

Oct 188:00 PM

The model of the atom at that point was known asthe planetary model:

the electrons were believed to orbit the nucleusthe way the planets orbit the sun.

http://www.uk-astronomy.com/atom.htm


22

October 26, 2017

Oct 1211:00 PM

Now: explain why so many positive charges can exist in the same

place????• Proton-proton attractive forces don‛t obey the “opposites attract” when in close proximity!• They do just the opposite- so do neutronsThe short range proton- proton, proton-neutron, neutron-neutron attractive forces are known as nuclear forces


23

October 26, 2017

Oct 1410:21 PM

Li36.94

Chemical symbol

Atomic #: whole #= # protons

Atomic mass # = # protons + # neutrons: weighted atomic mass


24

October 26, 2017

Nov 510:56 AM

Nuclear Symbols

Z##

# nuclear particles

# protons

#+/-

charge on the atom

protons+ neutrons


25

October 26, 2017

Oct 188:29 PM

summary of hydrogen isotopes:

Isotope NuclearSymbol

# ofprotons

# ofneutrons

# ofelectrons

hydrogen - 1 H-1

hydrogen-2 H-2hydrogen-3 H-3


26

October 26, 2017

Oct 188:41 PM

Isotope # of protons# of neutrons

Nuclear Symbol

carbon-12

carbon-13

carbon-14

C12

C13

C14


27

October 26, 2017

Oct 188:47 PM

Relative Atomic Masses*The actual mass of an atom of an element is so small, that it is not convenient to expressthem in grams.*Therefore: choose the mass of one key atom, and

call that "one atomic unit."


28

October 26, 2017

Oct 188:56 PM

• The standard : the carbon atom• The unit: one atomic mass unit, written:

a.m.u.> is 1/12 of the actual mass of a carbon-12

atom.

Relative Atomic Masses, continued


29

October 26, 2017

Oct 188:59 PM

weighted atomic averages.The weighted average atomic mass is the weighted average of all of the naturally occurring isotopes of a particular element.


30

October 26, 2017

Oct 248:35 AM


31

October 26, 2017

Oct 189:12 PM

Let's do this with isotopes

Summing the process:1. we multiply the atomic mass of each isotope by it's relative

abundance 2. Then add the results and 3. divide by 100 to find the weighted average.


32

October 26, 2017

Oct 189:24 PM

Step 1: multiply the amu by the abundance .005% x 234. 040 947 = 001.17020235.720 %x 235.043 924 = 169.2316252899.275% x 238.050 784 = 23632.4915816

amuamuamuamu

round to hundredths place AT The End

1. Isotopes of Uranium occur naturally in the following percentages:

Isotope name % abundance Atomic massa. Uranium 234: .005% 234. 040 947 a.m.u.b. Uranium 235 .720% 235.043 924 a.m.u.c. Uranium 238 99.275% 238.050 784 a.m.u.

Calculate the weighted average of the atomic mass of Uranium.


33

October 26, 2017

Oct 189:36 PM

5. A certain element exists as three natural isotopes as shown in the table below.Percent naturalIsotope Mass (amu) abundance Mass number1 19.99 244 90.51 % 202 20.99395 0.27 % 213 21.99138 9.22 % 22

Calculate the average atomic mass of this element.

19. 99244 × 90.51 =1809.5157 amu 20.99395 × 00.27 = 05.668 amu 21.99138 × 9.22 = 202.32 amu

2017.9

divide by 100 and round to 100ths: 20.18 amu


34

October 26, 2017

Oct 1911:16 PM

Counting Atoms1 AMU is based on the mass of an atom of C12

We can determine how many atoms we haveby relating it to this number and a unit called the MOLE

THE MOLE1 mole is the amount of a substance that contains the same number of particles as exactly 12 grams of Carbon12


35

October 26, 2017

Oct 239:58 AM

AVOGADRO'S NUMBER OR AVOGADRO'S CONSTANT

THE NUMBER OF PIECES IN ONE MOLE :

THIS IS EQUAL TO 6.022 X 1023 NO MATTER WHAT YOU ARE TALKING ABOUT!!!!DONUTS, EGGS, CARROTS...ELEPHANTS!


36

October 26, 2017

Oct 2310:07 AM

MolarMass

amount of mass in one

Mole of a substance.

OR_

http://www.hcc.mnscu.edu/chem/V.13/page_id_15835.html


37

October 26, 2017

Oct 314:37 PM

Examples:

Carbon: 1 atom of carbon is 12.01 a.m.u 1 mol of carbon is 12.01 g

Magnesium: 1 atom is 24.31 a.m.u. 1 mole is 24.31 g


38

October 26, 2017

Oct 314:38 PM

Compounds:

one molecule of water: H2O 2.02 + 16.00

18.02 a.m.u.

one mole of water: 18.02 g/mol


39

October 26, 2017

Oct 261:40 PM

Types of conversions we will be doing:1. Moles to mass2. Mass to moles3. # moles to # atoms4. # atoms to # of moles5. # atoms to mass6. Mass to # atoms


40

October 26, 2017

Oct 261:43 PM

mass

Determine the given (known) in your problemGo to the box that has the given in it.Determine which box has your unknownperform the operations in the arrow.

# moles # atoms÷ molar mass of element x 6.022 x1023

mass # moles # atoms÷ 6.022 x1023

xmolar mass of element


41

October 26, 2017

Oct 2310:23 AM

CuGiven

3.50 mole Cu = amount

?

mass = ?

# moles x molar mass = mass

3.50mol x 63.55 g/mole = mass

= 222.425 g Cumass = 222. g


42

October 26, 2017

Oct 2112:51 PM

Givenamount = 0.375mol K

mass = ?

# Moles x Molar mass = mass

mass=14.7g K

molar mass K: 39.10 g/mole

?

0.375 mole K. x 39.10 g/mo| = mass K


43

October 26, 2017

Oct 2112:57 PM

Givenamt= 0.0135 mol Na

?mass=?

amount in moles x Molar mass = mass

0.0135 mol Na x 22.99 g/mol =0.310g Na

molar mass Na = 22.99 g/mo|


44

October 26, 2017

Oct 2811:13 AM

Given

4.00 moles Al

?

# atoms

x 6.022. 1023 atoms/mole4.00 mol Al = # atoms24.088 x 1023 atoms Al

2.41 x 1024 atoms Al

= # atoms

6.022. 1023 atoms in one mol

# moles x atoms per mole = # atoms


45

October 26, 2017

Oct 3011:11 AM

# label # Label# label # Label


46

October 26, 2017

Oct 2312:51 PM

Known

3.01 x 1023 atoms Ag

?# moles

0.500 mole Ag

# atoms ÷ # atommole = # moles

3.01 x 1023 atoms 1 mole

6.022 x 1023 atoms

3.01. 1023 atoms Ag ÷ 6.022.1023 atoms/mole = # moles


47

October 26, 2017

Oct 2612:59 PM

known ?# atoms = 3.0x 1023 atoms F mass

3.0 x 1023 atoms F ÷ 6.022 x 1023 atoms F x 18.99 g/mole =mass

# atoms ÷ # atoms in one mole x molar mass = mass

3.0 x 1023 atoms F mole 18.99 g =mass F 6.022x 1023 atoms mole


48

October 26, 2017

Nov 710:34 AM

Dimensional analysis: do the math with only the units;

Determine the equationset up with units

grams moles

grams= grams

if the units match what you are after, plug in the numbers


49

October 26, 2017

Nov 1210:25 AM

• Mass to # atoms• # atoms to mass

2 step conversions:


50

October 26, 2017

Nov 35:29 PM

What is the mass, in grams, of 1.20x108 atoms of Cu?

Atoms to moles to mass

# atoms ÷ # atoms in one mole x the molar mass = mass of Cu

Pg. 86 Sample problem E

Given ?1.20 x 108 atoms Cu mass of Cu

1.20 x 108 atoms Cu ÷ 6.022 x 1023atoms/mole x 63. 55g/mol = massCu

.199 x 10 -15 mol Cu x 63.55 g/mol = mass Cu

1.27 x 10-14 g Cu


51

October 26, 2017

Nov 912:22 PM

#mol → mass#mol . molar mass = mass

mass → Mol#g ÷ molar mass = mol

1

# atoms →# moles 4 #atoms ÷ 6.022 x 1023 atoms/mole = # moles

# moles → # atoms# atoms x 6.022 x 1023 = # atoms

2

3

Move me to see notes


52

October 26, 2017

summary slide2

5 # atom --> mass# atoms ÷ 6.022 x 1023 x molar mass = mass (g)

6mass --> # atomsmass ÷ molar mass x 6.022 x 1023 atom/mole = # atoms


53

October 26, 2017

Nov 187:30 AM

Law of conservation of mass

Law of Definite Proportions

Attachments

PP CHEM107.ppt

Atomic Structure

Chemistry 1

Chapter 7

I. Early Atomic Theory

A. The Greeks

Democritus 400 BC

1. Coined the word atom

2. Different atoms for each material

Aristotle

1. Taught that all matter was composed of a continuous material called “hyle”.

ALCHEMISTS LAB

ALCHEMY

B. Europeans

1. Newton and Robert Boyle –

proposed atomic theory but had no proof.

2. Joseph Proust –

determined the Law of Definite Proportions.

3. Lavosier –

closed system reactions showed no mass changes.

DALTON’S ATOMIC THEORY

JOHN DALTON

II. Dalton’s Hypothesis

All matter is composed of extremely small particles called atoms

Atoms of a given element are identical in size, mass, and other properties. Atoms of different elements differ is size, mass, and other properties.

Atoms cannot be subdivided, created, or destroyed

Atoms of different elements combine in simple whole number rations to form chemical compounds

In chemical reactions, atoms are combined, separated, or rearranged.

This explains the conservation of mass- along with #3

LAW OF DEFINITE PROPORTIONS

LAW OF MULITPLE PROPORTIONS

Law of multiple proportions

C. Part 2 of the proposal is not entirely correct.

It was discovered that some atoms of an element are heavier than other atoms of the same element.

D. Law of Multiple Proportions - for elements that form more than 1 compound with each other.

SnO 119 to 16 1 to 1

SnO2 119 to 32 1 to 2

III. Early Research on Atomic Particles

A. Atoms consist of smaller particles

B. Cathode Ray Tube

1. + electrode (anode)

2. - electrode (cathode)

3. Rays moved from cathode to the anode.

CATHODE RAY TUBE

CRT

4. J.J. Thomson discovered they were electrons and calculated charge to mass ratio.

CRT IN MAGNETIC FIELD

CRT IN MAGNETIC FIELD

C. Robert Milikan-

Discovered the charge of a single electron through his famous oil drop experiment.

Mass was calculated to be 1/1837th that of a hydrogen atom.

MILIKAN OIL DROP EXPERIMENT

D. Goldstein -

Discovered protons using a modified cathode ray tube.

1. Thomson showed they were particles.

2. Their mass was calculated to be 1836 times the mass of an electron.

GOLDSTEIN’S CRT

E. Chadwick discovered neutrons.

IV. Isotopes and Atomic Number

A. If all atoms of an element were the same, the atomic mass of the element should have a whole number value. It did not.

B. J.J. Thomson observed two kinds of neon atoms, chemically alike but with different masses.

ISOTOPES OF HYDROGEN

ISOTOPES OF LITHIUM

ISOTOPE CHART

C. Henry Moseley -

Discovered the cause of the mass differences in atoms of the same element.

1. X-rays produced by all the atoms of an element had a characteristic wavelength

2. All atoms of an element had the same number of protons.

3. Atomic Number (Z) equals the number of protons.

4. Since atoms are neutral, the number of electrons must equal the number of protons.

5. That left the neutron as the cause of the mass differences in atoms of a given element.

6. It is the number of protons that give an element it’s characteristics.

D. New Atomic Theory

Takes into account the mass differences between atoms of a given element.

1. Nuclide - particular kind of atom containing a definite number of protons and neutrons.

2. Nucleon – particles that make up the nucleus.

3. Mass Number – (A) total number of nucleons.

A – Z = Neutrons

NUCLIDE CHART

V. The Nuclear Atom

A. Gold Foil Experiment

Was designed by Rutherford to determine how atoms were constructed.

GOLD FOIL APPARATUS

2. Some bullets were deflected, 1 in 8000 bounced back.

3. With a diameter of an atom between 100 – 500 pm, the diameter of the nucleus was calculated at 0.0012 to 0.0075pm.

4. Nucleus is about 1 trillionth the volume of the atom.

VI. Radioactivity

A. Becquerel discovered radioactivity. How??

B. Radioactivity – rays being produced spontaneously by unstable atomic nuclei.

C. Energy Released

1. 1 mol U-235 in chemical reaction releases 7.64*102 kj (764 kj)

2. 1 mol U-235 in nuclear change releases 1.90*1010 kj (19 000 000 000 kj)

VII. Atomic Structure

A. The Nucleus

1. Composed of Protons and Neutrons.

2. What holds the nucleus together?

3. Strong Nuclear Force over 1x10-15m.

4. Has a property that corresponds to spinning on an axis.

ATOMIC NUCLEUS

5. Electrons do not exist in the nucleus but can be emitted by one.

n -> p + e- and an anti-neutrion

B. Subatomic Particles

1. Leptons – light particles

2. Hadrons – heavy particles composed of quarks

a. Baryons (3)

b. Mesons (2)

3. antiparticles

4. Quarks

Proton’s Quark make up (UUD)

U quarks = (+2/3), D quarks = (-1/3)

(+2/3) + (+2/3) + (-1/3) = +1 Charge

Neutron (UDD)

(+2/3) + (-1/3) + (-1/3) = 0 Charge

Quarks are held together by exchanging gluons

ATOMIC STRUCTURE

PARTICL IDENTIFIER

FERMILAB

VIII. Radiation

A. Definition

B. Types

1. Alpha 42He

2. beta

3. gamma

VIII. Radiation

A. Unstable nuclei will eject a particle or energy to reach a more

stable state.

B. Types:

1. Alpha particle are helium nuclei 42 He

2. Beta particles are electrons

3. gamma rays are high energy X rays.

C. Transuranic elements are produced by bombarding stable nuclei

with accelerated particles.

1. these radioactives decay by particle or energy

emission or by capturing an electron from outside

the nucleus.

C. Transuranic elements – After Uranium

Are produced by bombarding stable nuclei with accelerated particles.

Seaborgium named after an Upper Peninsula native who became a famous scientist

IX. The Rutherford Bohr Atom

A. The electron and the nucleus

B. Planetary orbits

Orbital Motion

ELECTRON ORBITAL

LIGHT ABSORPTION

ORBIT JUMPING

C. Energy changes in electrons

The Photoelectric Effect

Electrons moving to higher orbits

Electrons falling to lower orbits

D. Definitions

1. spectroscopy

2. electromagnetic energy

3. frequency

4. wavelength

5. hertz

6. spectrum

7. amplitude

WAVE PARTS

X. Planck’s Hypothesis

A. Quantum Theory

B. Quanta – packets of energy

C. E = hf (6.63 x 10-34j/Hz)(frequency)

QUANTUM VESSEL

XI. Quantum Theory and Hydrogen

A. Absorption of light at specific wavelengths corresponded to definite energy changes.

B. Quanta - packets of energy- energy could be absorbed or emitted in whole numbers of quanta 1,2,3 etc.

C. Electrons had orbitals with definite energy levels.

D. Orbital Sizes

1. electrons move between orbitals by absorbing or releasing quanta of energy.

2. ground state – when all electrons are at the lowest possible energy levels.

3. H is about 53pm in radius.

E. Disagreement with other atoms-

Calculations that worked for hydrogen did not work for more complicated atoms.

XII. Atomic Mass

A.Protons and Neutrons – equal in mass

B.Electrons – almost massless

C.The Nucleus – most of atoms mass

D.Atomic Mass Units (amu)

Carbon 12 has a mass of 12 amu.

E.Isotopes

XIII. Average Atomic Mass

A. Mass Spectrometer – device used to find the masses of all the isotopes of an element.

CALCULATIONS

B. Calculations:

Si92.21% = 27.972 amu

4.70% = 28.976 amu

3.09% = 29.974 amu

(27.972 x 92.21)

+

(28.976 x 4.70)

+

(29.974 x 3.09)

100

= 28.08

CALCULATIONS

CALCULATION

LLA SI TAHT

SMART Notebook

Page 1Page 2Page 3Page 4Page 5Page 6Page 7Page 8Page 9Page 10Page 11Page 12Page 13Page 14Page 15Page 16Page 17Page 18Page 19Page 20Page 21Page 22Page 23Page 24Page 25Page 26Page 27Page 28Page 29Page 30Page 31Page 32Page 33Page 34Page 35Page 36Page 37Page 38Page 39Page 40Page 41Page 42Page 43Page 44Page 45Page 46Page 47Page 48Page 49Page 50Page 51Page 52Page 53Attachments Page 1

atoms, the building blocks of matter - niagara.k12.wi.us 3 notes .pdf · john dalton: english...

Documents