History of the AtomScientists and Their Contribution to
the Model of an Atom
Tuesday, October 8, 13
History of the Atom - Timeline
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Tuesday, October 8, 13
History of the Atom - Timeline
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
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Tuesday, October 8, 13
Democritus proposes
the 1st atomic theory
460 – 370 BC
History of the Atom - Timeline
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1743 – 1794
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - TimelineAntoine Lavoisier
makes a substantial number of contributions
to the field of Chemistry
1743 – 1794
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1743 – 1794
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1766 – 1844
1743 – 1794
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1766 – 1844
John Dalton proposes his
atomic theory in 1803
1743 – 1794
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1766 – 1844
1743 – 1794
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1766 – 1844
1743 – 1794
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1856 – 1940
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1766 – 1844
1743 – 1794
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1856 – 1940
J.J. Thomson discovers the electron and proposes the Plum Pudding Model in 1897
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1766 – 1844
1743 – 1794
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1856 – 1940
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1766 – 1844
1743 – 1794
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1856 – 1940
1871 – 1937
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1766 – 1844
1743 – 1794
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1856 – 1940
1871 – 1937
Ernest Rutherford performs the Gold Foil
Experiment in 1909
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1766 – 1844
1743 – 1794
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1856 – 1940
1871 – 1937
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1766 – 1844
1743 – 1794
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1856 – 1940
1871 – 1937
1885 – 1962
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1766 – 1844
1743 – 1794
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1856 – 1940
1871 – 1937
1885 – 1962
Niels Bohr proposes the Bohr Model in
1913
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1766 – 1844
1743 – 1794
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1856 – 1940
1871 – 1937
1885 – 1962
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1900
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1766 – 1844
1743 – 1794
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1856 – 1940
1871 – 1937
1885 – 1962
1887 – 1961
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1766 – 1844
1743 – 1794
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1856 – 1940
1871 – 1937
1885 – 1962
1887 – 1961
Erwin Schrodinger
describes the electron cloud in 1926
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1766 – 1844
1743 – 1794
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1856 – 1940
1871 – 1937
1885 – 1962
1887 – 1961
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1766 – 1844
1743 – 1794
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1856 – 1940
1871 – 1937
1885 – 1962
1887 – 1961
1891 – 1974
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1766 – 1844
1743 – 1794
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1856 – 1940
1871 – 1937
1885 – 1962
1887 – 1961
1891 – 1974
James Chadwick
discovered the neutron in in 1932
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Tuesday, October 8, 13
460 – 370 BC
History of the Atom - Timeline
1766 – 1844
1743 – 1794
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1856 – 1940
1871 – 1937
1885 – 1962
1887 – 1961
1891 – 1974
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Tuesday, October 8, 13
Democritus(460 BC – 370 BC)
Tuesday, October 8, 13
Democritus(460 BC – 370 BC)
Image taken from: https://reich-chemistry.wikispaces.com/T.+Glenn
+Time+Line+Project
Tuesday, October 8, 13
Democritus(460 BC – 370 BC)
• Proposed an Atomic Theory (along with his mentor Leucippus) which states that all atoms are small, hard, indivisible and indestructible particles made of a single material formed into different shapes and sizes.
Image taken from: https://reich-chemistry.wikispaces.com/T.+Glenn
+Time+Line+Project
Tuesday, October 8, 13
Democritus(460 BC – 370 BC)
• Proposed an Atomic Theory (along with his mentor Leucippus) which states that all atoms are small, hard, indivisible and indestructible particles made of a single material formed into different shapes and sizes.
• Aristotle did not support his atomic theory
Image taken from: https://reich-chemistry.wikispaces.com/T.+Glenn
+Time+Line+Project
Tuesday, October 8, 13
Some Early Ideas on Matter
Tuesday, October 8, 13
Anaxagoras (Greek, born 500 B.C.)–Suggested every substance had its own kind of “seeds” that clustered together to make the substance, much as our atoms cluster to make molecules.
Some Early Ideas on Matter
Tuesday, October 8, 13
Anaxagoras (Greek, born 500 B.C.)–Suggested every substance had its own kind of “seeds” that clustered together to make the substance, much as our atoms cluster to make molecules.
Some Early Ideas on Matter
Empedocles (Greek, born in Sicily, 490 B.C.)–Suggested there were only four basic seeds – earth, air, fire, and water. The elementary substances (atoms to us) combined in various ways to make everything.
Tuesday, October 8, 13
Anaxagoras (Greek, born 500 B.C.)–Suggested every substance had its own kind of “seeds” that clustered together to make the substance, much as our atoms cluster to make molecules.
Some Early Ideas on Matter
Empedocles (Greek, born in Sicily, 490 B.C.)–Suggested there were only four basic seeds – earth, air, fire, and water. The elementary substances (atoms to us) combined in various ways to make everything.
Democritus (Greek, born 470 B.C.)–Actually proposed the word atom (indivisible) because he believed that all matter consisted of such tiny units with voids between, an idea quite similar to our own beliefs. It was rejected by Aristotle and thus lost for 2000 years.
Tuesday, October 8, 13
Anaxagoras (Greek, born 500 B.C.)–Suggested every substance had its own kind of “seeds” that clustered together to make the substance, much as our atoms cluster to make molecules.
Some Early Ideas on Matter
Empedocles (Greek, born in Sicily, 490 B.C.)–Suggested there were only four basic seeds – earth, air, fire, and water. The elementary substances (atoms to us) combined in various ways to make everything.
Democritus (Greek, born 470 B.C.)–Actually proposed the word atom (indivisible) because he believed that all matter consisted of such tiny units with voids between, an idea quite similar to our own beliefs. It was rejected by Aristotle and thus lost for 2000 years.
Aristotle (Greek, born 384 B.C.)–Added the idea of “qualities” – heat, cold, dryness, moisture – as basic elements which combined as shown in the diagram (previous page). Hot + dry made fire; hot + wet made air, and so on.
Tuesday, October 8, 13
Anaxagoras (Greek, born 500 B.C.)–Suggested every substance had its own kind of “seeds” that clustered together to make the substance, much as our atoms cluster to make molecules.
Some Early Ideas on Matter
Empedocles (Greek, born in Sicily, 490 B.C.)–Suggested there were only four basic seeds – earth, air, fire, and water. The elementary substances (atoms to us) combined in various ways to make everything.
Democritus (Greek, born 470 B.C.)–Actually proposed the word atom (indivisible) because he believed that all matter consisted of such tiny units with voids between, an idea quite similar to our own beliefs. It was rejected by Aristotle and thus lost for 2000 years.
Aristotle (Greek, born 384 B.C.)–Added the idea of “qualities” – heat, cold, dryness, moisture – as basic elements which combined as shown in the diagram (previous page). Hot + dry made fire; hot + wet made air, and so on.
Tuesday, October 8, 13
Alchemy
Tuesday, October 8, 13
Alchemy
• After that chemistry was ruled by alchemy.
• They believed that they could take any cheap metals and turn them into gold. This is called transmutation.
• Alchemists were almost like magicians.– elixirs, physical immortality
Tuesday, October 8, 13
Contributionsof alchemists:
Tuesday, October 8, 13
Contributionsof alchemists:
Information about elements
Tuesday, October 8, 13
Contributionsof alchemists:
Information about elements - the elements mercury, sulfur, and antimony were discovered
Tuesday, October 8, 13
Contributionsof alchemists:
Information about elements - the elements mercury, sulfur, and antimony were discovered- properties of some elements
Tuesday, October 8, 13
Contributionsof alchemists:
Information about elements - the elements mercury, sulfur, and antimony were discovered- properties of some elements
Develop lab apparatus / procedures / experimental techniques
Tuesday, October 8, 13
Contributionsof alchemists:
Information about elements - the elements mercury, sulfur, and antimony were discovered- properties of some elements
Develop lab apparatus / procedures / experimental techniques - alchemists learned how to prepare acids.
Tuesday, October 8, 13
Contributionsof alchemists:
Information about elements - the elements mercury, sulfur, and antimony were discovered- properties of some elements
Develop lab apparatus / procedures / experimental techniques - alchemists learned how to prepare acids. - developed several alloys
Tuesday, October 8, 13
Contributionsof alchemists:
Information about elements - the elements mercury, sulfur, and antimony were discovered- properties of some elements
Develop lab apparatus / procedures / experimental techniques - alchemists learned how to prepare acids. - developed several alloys - new glassware
Tuesday, October 8, 13
Antoine Lavoisier (1743 – 1794)
Tuesday, October 8, 13
Antoine Lavoisier (1743 – 1794)
Image taken from: www.ldeo.columbia.edu/.../v1001/
geotime2.html
Tuesday, October 8, 13
Antoine Lavoisier (1743 – 1794) • Known as the “Father of Modern
Chemistry”
Image taken from: www.ldeo.columbia.edu/.../v1001/
geotime2.html
Tuesday, October 8, 13
Antoine Lavoisier (1743 – 1794) • Known as the “Father of Modern
Chemistry”• Was the first person to generate a list of
thirty-three elements in his textbook
Image taken from: www.ldeo.columbia.edu/.../v1001/
geotime2.html
Tuesday, October 8, 13
Antoine Lavoisier (1743 – 1794) • Known as the “Father of Modern
Chemistry”• Was the first person to generate a list of
thirty-three elements in his textbook• Devised the metric system
Image taken from: www.ldeo.columbia.edu/.../v1001/
geotime2.html
Tuesday, October 8, 13
Antoine Lavoisier (1743 – 1794) • Known as the “Father of Modern
Chemistry”• Was the first person to generate a list of
thirty-three elements in his textbook• Devised the metric system• Was married to a 13-year old Marie-Anne
Pierette Paulze; she assisted him with much of his work
Image taken from: www.ldeo.columbia.edu/.../v1001/
geotime2.html
Tuesday, October 8, 13
Antoine Lavoisier (1743 – 1794) • Known as the “Father of Modern
Chemistry”• Was the first person to generate a list of
thirty-three elements in his textbook• Devised the metric system• Was married to a 13-year old Marie-Anne
Pierette Paulze; she assisted him with much of his work
• Was a tax-collector that was consequently guillotined during the French Revolution
Image taken from: www.ldeo.columbia.edu/.../v1001/
geotime2.html
Tuesday, October 8, 13
Antoine Lavoisier (1743 – 1794) • Known as the “Father of Modern
Chemistry”• Was the first person to generate a list of
thirty-three elements in his textbook• Devised the metric system• Was married to a 13-year old Marie-Anne
Pierette Paulze; she assisted him with much of his work
• Was a tax-collector that was consequently guillotined during the French Revolution
• Discovered/proposed that combustion occurs when oxygen combines with other elements
Image taken from: www.ldeo.columbia.edu/.../v1001/
geotime2.html
Tuesday, October 8, 13
Antoine Lavoisier (1743 – 1794) • Known as the “Father of Modern
Chemistry”• Was the first person to generate a list of
thirty-three elements in his textbook• Devised the metric system• Was married to a 13-year old Marie-Anne
Pierette Paulze; she assisted him with much of his work
• Was a tax-collector that was consequently guillotined during the French Revolution
• Discovered/proposed that combustion occurs when oxygen combines with other elements
• Discovered/proposed the Law of Conservation of Mass (or Matter) which states, in a chemical reaction, matter is neither created nor destroyed
Image taken from: www.ldeo.columbia.edu/.../v1001/
geotime2.html
Tuesday, October 8, 13
John Dalton (1766 – 1844)
Tuesday, October 8, 13
John Dalton (1766 – 1844)
Image taken from: chemistry.about.com/.../John-
Dalton.htm
Tuesday, October 8, 13
John Dalton (1766 – 1844)
• In 1803, proposed an Atomic Theory which states:
Image taken from: chemistry.about.com/.../John-
Dalton.htm
Tuesday, October 8, 13
John Dalton (1766 – 1844)
• In 1803, proposed an Atomic Theory which states:o All substances are made of atoms;
atoms are small particles that cannot be created, divided, or destroyed.
Image taken from: chemistry.about.com/.../John-
Dalton.htm
Tuesday, October 8, 13
John Dalton (1766 – 1844)
• In 1803, proposed an Atomic Theory which states:o All substances are made of atoms;
atoms are small particles that cannot be created, divided, or destroyed.
o Atoms of the same element are exactly alike, and atoms of different elements are different
Image taken from: chemistry.about.com/.../John-
Dalton.htm
Tuesday, October 8, 13
John Dalton (1766 – 1844)
• In 1803, proposed an Atomic Theory which states:o All substances are made of atoms;
atoms are small particles that cannot be created, divided, or destroyed.
o Atoms of the same element are exactly alike, and atoms of different elements are different
o Atoms join with other atoms to make new substances
Image taken from: chemistry.about.com/.../John-
Dalton.htm
Tuesday, October 8, 13
John Dalton (1766 – 1844)
• In 1803, proposed an Atomic Theory which states:o All substances are made of atoms;
atoms are small particles that cannot be created, divided, or destroyed.
o Atoms of the same element are exactly alike, and atoms of different elements are different
o Atoms join with other atoms to make new substances
• Calculated the atomic weights of many various elements Image taken from:
chemistry.about.com/.../John-Dalton.htm
Tuesday, October 8, 13
John Dalton (1766 – 1844)
• In 1803, proposed an Atomic Theory which states:o All substances are made of atoms;
atoms are small particles that cannot be created, divided, or destroyed.
o Atoms of the same element are exactly alike, and atoms of different elements are different
o Atoms join with other atoms to make new substances
• Calculated the atomic weights of many various elements
• Was a teacher at a very young age
Image taken from: chemistry.about.com/.../John-
Dalton.htm
Tuesday, October 8, 13
John Dalton (1766 – 1844)
• In 1803, proposed an Atomic Theory which states:o All substances are made of atoms;
atoms are small particles that cannot be created, divided, or destroyed.
o Atoms of the same element are exactly alike, and atoms of different elements are different
o Atoms join with other atoms to make new substances
• Calculated the atomic weights of many various elements
• Was a teacher at a very young age • Was color blind
Image taken from: chemistry.about.com/.../John-
Dalton.htm
Tuesday, October 8, 13
Dalton’s Atomic Theory (1808)
Tuesday, October 8, 13
Dalton’s Atomic Theory (1808)
1. All matter consists of tiny particles. Dalton, like the Greeks, called these particles “atoms”.
Tuesday, October 8, 13
Dalton’s Atomic Theory (1808)
1. All matter consists of tiny particles. Dalton, like the Greeks, called these particles “atoms”.
2. Atoms of one element can neither be subdivided nor changed into atoms of any other element.
Tuesday, October 8, 13
Dalton’s Atomic Theory (1808)
1. All matter consists of tiny particles. Dalton, like the Greeks, called these particles “atoms”.
2. Atoms of one element can neither be subdivided nor changed into atoms of any other element.
3. Atoms can neither be created nor destroyed.
Tuesday, October 8, 13
Dalton’s Atomic Theory (1808)
1. All matter consists of tiny particles. Dalton, like the Greeks, called these particles “atoms”.
2. Atoms of one element can neither be subdivided nor changed into atoms of any other element.
3. Atoms can neither be created nor destroyed.
4. All atoms of the same element are identical in mass, size, and other properties.
Tuesday, October 8, 13
Dalton’s Atomic Theory (1808)
1. All matter consists of tiny particles. Dalton, like the Greeks, called these particles “atoms”.
2. Atoms of one element can neither be subdivided nor changed into atoms of any other element.
3. Atoms can neither be created nor destroyed.
4. All atoms of the same element are identical in mass, size, and other properties.
5. Atoms of one element differ in mass and other properties from atoms of other elements.
Tuesday, October 8, 13
Dalton’s Atomic Theory (1808)
1. All matter consists of tiny particles. Dalton, like the Greeks, called these particles “atoms”.
2. Atoms of one element can neither be subdivided nor changed into atoms of any other element.
3. Atoms can neither be created nor destroyed.
4. All atoms of the same element are identical in mass, size, and other properties.
6. In compounds, atoms of different elements combine in simple, whole number ratios.
5. Atoms of one element differ in mass and other properties from atoms of other elements.
Tuesday, October 8, 13
Dalton’s Atomic Theory (1808)
1. All matter consists of tiny particles. Dalton, like the Greeks, called these particles “atoms”.
2. Atoms of one element can neither be subdivided nor changed into atoms of any other element.
3. Atoms can neither be created nor destroyed.
4. All atoms of the same element are identical in mass, size, and other properties.
6. In compounds, atoms of different elements combine in simple, whole number ratios.
5. Atoms of one element differ in mass and other properties from atoms of other elements.
Tuesday, October 8, 13
10
Tuesday, October 8, 13
Dalton’s symbols, 1808
Tuesday, October 8, 13
Dalton’s atomic weights, 1808
Tuesday, October 8, 13
• Michael Faraday (1825)- Split compounds by electrolysis and showed that atoms have electrical properties
• 1833 Michael Faraday discovers quantitative laws of electrochemical deposition.
• He introduces the terms electrode, cathode, anode, ion, anion, cation, electrolyte.
• He establishes that a definite quantity of electricity is associated with each atom of 13
Michael Faraday(1791-1867)
Tuesday, October 8, 13
J.J. Thomson (1856 – 1940)
Tuesday, October 8, 13
J.J. Thomson (1856 – 1940)
Image taken from: www.wired.com/.../news/2008/04/
dayintech_0430
Tuesday, October 8, 13
J.J. Thomson (1856 – 1940)
• Proved that an atom can be divided into smaller parts
Image taken from: www.wired.com/.../news/2008/04/
dayintech_0430
Tuesday, October 8, 13
J.J. Thomson (1856 – 1940)
• Proved that an atom can be divided into smaller parts
• While experimenting with cathode-ray tubes, discovered corpuscles, which were later called electrons
Image taken from: www.wired.com/.../news/2008/04/
dayintech_0430
Tuesday, October 8, 13
J.J. Thomson (1856 – 1940)
• Proved that an atom can be divided into smaller parts
• While experimenting with cathode-ray tubes, discovered corpuscles, which were later called electrons
• Stated that the atom is neutral
Image taken from: www.wired.com/.../news/2008/04/
dayintech_0430
Tuesday, October 8, 13
J.J. Thomson (1856 – 1940)
• Proved that an atom can be divided into smaller parts
• While experimenting with cathode-ray tubes, discovered corpuscles, which were later called electrons
• Stated that the atom is neutral• In 1897, proposed the Plum Pudding
Model which states that atoms mostly consist of positively charged material with negatively charged particles (electrons) located throughout the positive material
Image taken from: www.wired.com/.../news/2008/04/
dayintech_0430
Tuesday, October 8, 13
J.J. Thomson (1856 – 1940)
• Proved that an atom can be divided into smaller parts
• While experimenting with cathode-ray tubes, discovered corpuscles, which were later called electrons
• Stated that the atom is neutral• In 1897, proposed the Plum Pudding
Model which states that atoms mostly consist of positively charged material with negatively charged particles (electrons) located throughout the positive material
• Won a Nobel Prize
Image taken from: www.wired.com/.../news/2008/04/
dayintech_0430
Tuesday, October 8, 13
Discovered by J.J. Thomson. He said the atom was a
sphere of positive electricity, with negative particles throughout. This came around right after he
discovered the electron.Tuesday, October 8, 13
He was by far the most famous American scientist. He wanted to find the electrical charge of electrons. He measured water droplets, and that wasn’t successful, so he measured oil droplets, where all this proved electrons were negatively charged. He also was a professor for many years, and wrote many textbooks on chemistry.
http://www.chemistryexplained.com/images/chfa_03_img0536.jpg
Robert Millikan
Tuesday, October 8, 13
• Robert Millikan (1868-1923)– Oil drop experiment – 1909
Tuesday, October 8, 13
Ernest Rutherford (1871 – 1937)
Tuesday, October 8, 13
Ernest Rutherford (1871 – 1937)
Image taken from: http://www.scientific-web.com/en/Physics/Biographies/ErnestRutherford.html
Tuesday, October 8, 13
Ernest Rutherford (1871 – 1937)
• In 1909, performed the Gold Foil Experiment and suggested the following characteristics of the atom:
Image taken from: http://www.scientific-web.com/en/Physics/Biographies/ErnestRutherford.html
Tuesday, October 8, 13
Ernest Rutherford (1871 – 1937)
• In 1909, performed the Gold Foil Experiment and suggested the following characteristics of the atom:o It consists of a small core, or nucleus,
that contains most of the mass of the atom
Image taken from: http://www.scientific-web.com/en/Physics/Biographies/ErnestRutherford.html
Tuesday, October 8, 13
Ernest Rutherford (1871 – 1937)
• In 1909, performed the Gold Foil Experiment and suggested the following characteristics of the atom:o It consists of a small core, or nucleus,
that contains most of the mass of the atom
o This nucleus is made up of particles called protons, which have a positive charge
Image taken from: http://www.scientific-web.com/en/Physics/Biographies/ErnestRutherford.html
Tuesday, October 8, 13
Ernest Rutherford (1871 – 1937)
• In 1909, performed the Gold Foil Experiment and suggested the following characteristics of the atom:o It consists of a small core, or nucleus,
that contains most of the mass of the atom
o This nucleus is made up of particles called protons, which have a positive charge
o The protons are surrounded by negatively charged electrons, but most of the atom is actually empty space
Image taken from: http://www.scientific-web.com/en/Physics/Biographies/ErnestRutherford.html
Tuesday, October 8, 13
Ernest Rutherford (1871 – 1937)
• In 1909, performed the Gold Foil Experiment and suggested the following characteristics of the atom:o It consists of a small core, or nucleus,
that contains most of the mass of the atom
o This nucleus is made up of particles called protons, which have a positive charge
o The protons are surrounded by negatively charged electrons, but most of the atom is actually empty space
• Did extensive work on radioactivity (alpha & beta particles, gamma rays/waves) and was referred to as the “Father of Nuclear Physics”
Image taken from: http://www.scientific-web.com/en/Physics/Biographies/ErnestRutherford.html
Tuesday, October 8, 13
Ernest Rutherford (1871 – 1937)
• In 1909, performed the Gold Foil Experiment and suggested the following characteristics of the atom:o It consists of a small core, or nucleus,
that contains most of the mass of the atom
o This nucleus is made up of particles called protons, which have a positive charge
o The protons are surrounded by negatively charged electrons, but most of the atom is actually empty space
• Did extensive work on radioactivity (alpha & beta particles, gamma rays/waves) and was referred to as the “Father of Nuclear Physics”
• Won a Nobel Prize
Image taken from: http://www.scientific-web.com/en/Physics/Biographies/ErnestRutherford.html
Tuesday, October 8, 13
Ernest Rutherford (1871 – 1937)
• In 1909, performed the Gold Foil Experiment and suggested the following characteristics of the atom:o It consists of a small core, or nucleus,
that contains most of the mass of the atom
o This nucleus is made up of particles called protons, which have a positive charge
o The protons are surrounded by negatively charged electrons, but most of the atom is actually empty space
• Did extensive work on radioactivity (alpha & beta particles, gamma rays/waves) and was referred to as the “Father of Nuclear Physics”
• Won a Nobel Prize• Was a student of J.J. Thomson
Image taken from: http://www.scientific-web.com/en/Physics/Biographies/ErnestRutherford.html
Tuesday, October 8, 13
Ernest Rutherford (1871 – 1937)
• In 1909, performed the Gold Foil Experiment and suggested the following characteristics of the atom:o It consists of a small core, or nucleus,
that contains most of the mass of the atom
o This nucleus is made up of particles called protons, which have a positive charge
o The protons are surrounded by negatively charged electrons, but most of the atom is actually empty space
• Did extensive work on radioactivity (alpha & beta particles, gamma rays/waves) and was referred to as the “Father of Nuclear Physics”
• Won a Nobel Prize• Was a student of J.J. Thomson • Was on the New Zealand $100 bill
Image taken from: http://www.scientific-web.com/en/Physics/Biographies/ErnestRutherford.html
Tuesday, October 8, 13
Gold-Foil Experiment
19
Tuesday, October 8, 13
Niels Bohr (1885 – 1962)
Tuesday, October 8, 13
Niels Bohr (1885 – 1962)
Image taken from: commons.wikimedia.org/wiki/
File:Niels_Bohr.jpg
Tuesday, October 8, 13
Niels Bohr (1885 – 1962)
• In 1913, proposed the Bohr Model, which suggests that electrons travel around the nucleus of an atom in orbits or definite paths. Additionally, the electrons can jump from a path in one level to a path in another level (depending on their energy)
Image taken from: commons.wikimedia.org/wiki/
File:Niels_Bohr.jpg
Tuesday, October 8, 13
Niels Bohr (1885 – 1962)
• In 1913, proposed the Bohr Model, which suggests that electrons travel around the nucleus of an atom in orbits or definite paths. Additionally, the electrons can jump from a path in one level to a path in another level (depending on their energy)
• Won a Nobel Prize
Image taken from: commons.wikimedia.org/wiki/
File:Niels_Bohr.jpg
Tuesday, October 8, 13
Niels Bohr (1885 – 1962)
• In 1913, proposed the Bohr Model, which suggests that electrons travel around the nucleus of an atom in orbits or definite paths. Additionally, the electrons can jump from a path in one level to a path in another level (depending on their energy)
• Won a Nobel Prize • Worked with Ernest Rutherford
Image taken from: commons.wikimedia.org/wiki/
File:Niels_Bohr.jpg
Tuesday, October 8, 13
Quantum Mechanics
Microscope
Electron
γ
Werner Heisenberg~1926
Tuesday, October 8, 13
Quantum Mechanics
• Heisenberg Uncertainty Principle– Impossible to know both the velocity and
position of an electron at the same time
Microscope
Electron
γ
Werner Heisenberg~1926
Tuesday, October 8, 13
Quantum Mechanics
• Heisenberg Uncertainty Principle– Impossible to know both the velocity and
position of an electron at the same time
Microscope
Electron
γ
Werner Heisenberg~1926
Tuesday, October 8, 13
Quantum Mechanics
• Heisenberg Uncertainty Principle– Impossible to know both the velocity and
position of an electron at the same time
Microscope
Electron
γ
Werner Heisenberg~1926
Tuesday, October 8, 13
Erwin Schrodinger (1887-1961)
Tuesday, October 8, 13
Erwin Schrodinger (1887-1961)
Image taken from: nobelprize.org/.../1933/schrodinger-
bio.html
Tuesday, October 8, 13
Erwin Schrodinger (1887-1961)
• In 1926, he further explained the nature of electrons in an atom by stating that the exact location of an electron cannot be stated; therefore, it is more accurate to view the electrons in regions called electron clouds; electron clouds are places where the electrons are likely to be found Image taken from:
nobelprize.org/.../1933/schrodinger-bio.html
Tuesday, October 8, 13
Erwin Schrodinger (1887-1961)
• In 1926, he further explained the nature of electrons in an atom by stating that the exact location of an electron cannot be stated; therefore, it is more accurate to view the electrons in regions called electron clouds; electron clouds are places where the electrons are likely to be found
• Did extensive work on the Wave formula Schrodinger equation
Image taken from: nobelprize.org/.../1933/schrodinger-
bio.html
Tuesday, October 8, 13
Erwin Schrodinger (1887-1961)
• In 1926, he further explained the nature of electrons in an atom by stating that the exact location of an electron cannot be stated; therefore, it is more accurate to view the electrons in regions called electron clouds; electron clouds are places where the electrons are likely to be found
• Did extensive work on the Wave formula Schrodinger equation
• Won a Nobel Prize
Image taken from: nobelprize.org/.../1933/schrodinger-
bio.html
Tuesday, October 8, 13
James Chadwick (1891 – 1974)
Tuesday, October 8, 13
James Chadwick (1891 – 1974)
Image taken from: www.wired.com/.../news/2009/02/
dayintech_0227
Tuesday, October 8, 13
James Chadwick (1891 – 1974)
• Realized that the atomic mass of most elements was double the number of protons discovery of the neutron in 1932
Image taken from: www.wired.com/.../news/2009/02/
dayintech_0227
Tuesday, October 8, 13
James Chadwick (1891 – 1974)
• Realized that the atomic mass of most elements was double the number of protons discovery of the neutron in 1932
• Worked on the Manhattan Project
Image taken from: www.wired.com/.../news/2009/02/
dayintech_0227
Tuesday, October 8, 13
James Chadwick (1891 – 1974)
• Realized that the atomic mass of most elements was double the number of protons discovery of the neutron in 1932
• Worked on the Manhattan Project
• Worked with Ernest Rutherford
Image taken from: www.wired.com/.../news/2009/02/
dayintech_0227
Tuesday, October 8, 13
James Chadwick (1891 – 1974)
• Realized that the atomic mass of most elements was double the number of protons discovery of the neutron in 1932
• Worked on the Manhattan Project
• Worked with Ernest Rutherford• Won a Nobel Prize
Image taken from: www.wired.com/.../news/2009/02/
dayintech_0227
Tuesday, October 8, 13
Progression of the Atomic Model
The structure of an atom, according to:
Tuesday, October 8, 13
Progression of the Atomic Model
The structure of an atom, according to:
Democritus & John Dalton
Tuesday, October 8, 13
Progression of the Atomic Model
The structure of an atom, according to:
Tuesday, October 8, 13
Progression of the Atomic Model
The structure of an atom, according to:
J.J. Thomson
+-- --
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Tuesday, October 8, 13
Progression of the Atomic Model
The structure of an atom, according to:
Tuesday, October 8, 13
Progression of the Atomic Model
The structure of an atom, according to:
Ernest Rutherford
Tuesday, October 8, 13
Progression of the Atomic Model
The structure of an atom, according to:
Tuesday, October 8, 13
Progression of the Atomic Model
The structure of an atom, according to:
Neils Bohr
Tuesday, October 8, 13
Progression of the Atomic Model
The structure of an atom, according to:
Tuesday, October 8, 13
Progression of the Atomic Model
The structure of an atom, according to:
Erwin Schrodinger
Tuesday, October 8, 13
Progression of the Atomic Model
The structure of an atom, according to:
Tuesday, October 8, 13
Progression of the Atomic Model
The structure of an atom, according to:
James Chadwick
Tuesday, October 8, 13
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