~450BC Who was the first to propose that matter was made of tiny indivisible particles ?
-
Upload
felicity-atkinson -
Category
Documents
-
view
226 -
download
2
Transcript of ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?
![Page 1: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/1.jpg)
![Page 2: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/2.jpg)
![Page 3: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/3.jpg)
~450BC
![Page 4: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/4.jpg)
Who was the first to propose that matter was made of tiny indivisible particles ?
![Page 5: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/5.jpg)
Democritus’s atom
matter was made up of tiny invisible indivisible particles in constant motion
surrounded by an empty space (void) solid (no void inside) eternal (indestructible) Differ from one another in shape, size,
arrangement
![Page 6: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/6.jpg)
Aristotle
Disapproved of Democritus’ idea of atoms
Believed that all matter was comprised ofEarth, wind, fire and water
![Page 7: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/7.jpg)
Dalton’s Atom
The Atom – Circa 1800
indivisible
![Page 8: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/8.jpg)
1st Modern Atomic Theory
1. Matter consists of tiny particles called atoms.
2. Atoms of one element are alike and are different from atoms of another element.
3. Atoms are indestructible and unchangeable (law conservation of matter). Lavoisier
4. Atoms combine in simple whole number ratios to form compounds (law of definite proportion).Lavoisier
![Page 9: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/9.jpg)
Lavoisier (early 1700’s)
Father of modern chemistry
Law of conservation of matter –
matter not created not destroyed
![Page 10: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/10.jpg)
Faraday 1839 Electrolysis experiments
Structure of atoms related to electricity
Charge is somehow involved in binding elements together to form compounds
![Page 11: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/11.jpg)
Crooke’s tube/Cathode Ray tube
2 electrodes Cathode: negatively charged electrode Anode: positively charged electrode
Rays from cathode to anode
![Page 12: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/12.jpg)
Deflection of a charged particle
1. mass 2. velocity 3. charge of the particle 4. Strength of magnet 5. amount of charge on the
plates
![Page 13: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/13.jpg)
![Page 14: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/14.jpg)
JJ Thomson
Experiments with cathode ray tube:
Conclusion: Cathode ray was a stream of
negatively charged particles called electrons
Later protons were found going in an opposite direction
![Page 15: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/15.jpg)
Plum Pudding Model
Sphere of positive charge
with electrons embedded in it.
![Page 16: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/16.jpg)
Millikan’s Oil Drop Experiment 1909
Determined charge of electron using Thomson’s charge to mass ratio
Charge = 1.6 X 10-
19C
![Page 17: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/17.jpg)
cathode ray tube gave offX-rays
Roentgen 1870’s
![Page 18: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/18.jpg)
Becquerel Discovers
radioactivity(spontaneous emission of particles or rays) when photographic film becomes exposed in the presence of a sample of uranium
Refers to Pierre and Marie Curie
![Page 19: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/19.jpg)
Marie and Pierre Curie (1900’s)
Discovered Radium (Ra) and Polonium (Po).
Marie won 2 Nobel prizes
Marie died of cancer and Pierre was killed by a horse drawn milk truck
Daughter Irene continued their work
![Page 20: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/20.jpg)
Rutherford 1909
Lead Box Experiment3 types of radiation from radioactive substances: α, β, γ
Gold foil experiment Positively charged alpha
particles (He nucleus) were shot at a thin piece of gold foil
Expected α particles to go right through
![Page 21: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/21.jpg)
Gold Foil Experiment
![Page 22: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/22.jpg)
![Page 23: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/23.jpg)
Rutherford’s Conclusion
-Atom mostly empty space
-Positive charge and mass concentrated in tiny dense -nucleus
![Page 24: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/24.jpg)
The neutron
Chadwick – 1932• Neutral radiation by nuclear
bombardment nuclear reaction• No charge but same mass as
proton
![Page 25: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/25.jpg)
![Page 26: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/26.jpg)
Neutral Carbon-12 atom
![Page 27: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/27.jpg)
Subatomic particles Proton
Inside nucleus +1
1 amu Neutron
Inside nucleus 0 1amu
Electron Outside nucleus -1 O amu(1/2000amu)
![Page 28: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/28.jpg)
Don’t get confused Atomic number
number of protons (on periodic table- top)
Mass Numbernumber of protons plus neutrons(not on periodic table)
Atomic Massthe weighted average of the massnumbers for all the isotopes of the atom(on periodic table – bottom)
![Page 29: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/29.jpg)
Symbols
Name-mass number
charge
XMass number
Atomic number
![Page 30: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/30.jpg)
Atoms
Protons=electrons
Atoms have no charge
![Page 31: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/31.jpg)
ISOTOPES
Atoms with the same number of protons but a different number of neutrons.
![Page 32: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/32.jpg)
Examples
Hydrogen-3 H
Hydrogen-2 H
Hydrogen-1 H
3
1
1
2
1
1
1
![Page 33: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/33.jpg)
Ions
Atoms that gain or lose electrons and become charged
Charge= protons- electrons
![Page 34: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/34.jpg)
Practice with ions
1. Write the symbol for calcium+2-41
How many protons, electron, neutrons
2. Write the symbol for oxygen-2-18.
How many protons, electron, neutrons?
![Page 35: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/35.jpg)
Atomic Mass
Make table:
MassX Abundance =
Atomic Mass= __________
![Page 36: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/36.jpg)
Atomic Mass
Make table:
MassX Abundance = ________
Cu-63 69.1% =
Cu-65 30.9% = +_________
Atomic Mass= __________
![Page 37: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/37.jpg)
Atomic mass
Element X has 2 isotopes X-10 and X-11. If the atomic mass is 10.8, what is the abundance of each?
![Page 38: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/38.jpg)
Pennies
Pre 1982 – mostly copper penny cost more than a penny to make
Except in 1943 pennies were zinc coated steel – “steel pennies”
Post 1982 – 97% zinc coated with copper since zinc is less expensive than copper
![Page 39: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/39.jpg)
What image did the early Greeks have of atoms?
![Page 40: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/40.jpg)
Further developments
Moseley: found elements contain a unique positive charge Number of protons in nucleus is what
determines the identity of the element Periodic table arranged according to atomic
number Chadwick (1930’s)
Discovers neutron
![Page 41: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/41.jpg)
Practice
1. Write the symbol for sodium-24
How many protons, electron and neutrons?
2. Write the symbol for Tin-123
How many protons, electron and neutrons?
![Page 42: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/42.jpg)
Proust 1799
Law of constant composition
(law of definite proportions)
Observed that a compound always contained the same elements in the same proportion by mass
example: water is always 88.9% oxygen and 11.1% hydrogen by mass
![Page 43: ~450BC Who was the first to propose that matter was made of tiny indivisible particles ?](https://reader035.fdocuments.in/reader035/viewer/2022062408/56649ee75503460f94bf7649/html5/thumbnails/43.jpg)
Calculate the atomic masses
• Copper-63 69.1% Copper-65 30.9%
• Uranium-234 .001% Uranium-235 .71% Uranium-238 99.23%