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History of the Atom Model

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Presentation on theme: "History of the Atom Model"— Presentation transcript:

1 History of the Atom Model
Air, earth, fire & water 450 BC Democritus (Greek)- World was made of 2 things: Empty space Tiny particles call atoms (Atomus= indivisible) Aristotle (Greek) Matter is continuous and not made of smaller particles PROBLEM: Neither had any evidence.

2 History of the Atom Model
1782 Antonine Lavoisier (French)- Law of Conservation of Matter (mass) Matter is neither created Nor destroyed, it is only rearranged. Mass of reactants = Mass of products

3 History of the Atom Model
1799 Joseph Proust (French)- Law of Definite Proportions Atoms must combine in whole number ratios. H vs H0 ½

4 History of the Atom Model
1799 Joseph Proust (French)- Law of Multiple Proportions Atoms can combine in different whole number ratios. H vs H202

5 Modern Atomic Theory (MAT) Developing
1803 John Dalton (English)- “Father of Modern Atomic Theory” Started teaching at 12 years old.

6 Dalton’s Atomic Theory
All matter is made up of atoms. Atoms are the smallest fundamental units of matter.

7 Dalton’s Atomic Theory
TRUE All matter is made up of atoms. Atoms are the smallest fundamental units of matter.

8 Dalton’s Atomic Theory
TRUE All matter is made up of atoms. Atoms are the smallest fundamental units of matter. All elements consist of atoms which are indivisible & indestructible.

9 Dalton’s Atomic Theory
TRUE All matter is made up of atoms. Atoms are the smallest fundamental units of matter. All elements consist of atoms which are indivisible & indestructible. FALSE Nuclear reactions

10 Dalton’s Atomic Theory
TRUE All matter is made up of atoms. Atoms are the smallest fundamental units of matter. All elements consist of atoms which are indivisible & indestructible. All atoms of the same element are identical in size, shape & mass. FALSE Nuclear reactions

11 Dalton’s Atomic Theory
TRUE All matter is made up of atoms. Atoms are the smallest fundamental units of matter. All elements consist of atoms which are indivisible & indestructible. All atoms of the same element are identical in size, shape & mass. FALSE Nuclear reactions FALSE Isotopes

12 Dalton’s Atomic Theory
TRUE All matter is made up of atoms. Atoms are the smallest fundamental units of matter. All elements consist of atoms which are indivisible & indestructible. All atoms of the same element are identical in size, shape & mass. Atoms of different elements are different in size, shape, & mass. FALSE Nuclear reactions FALSE Isotopes

13 Dalton’s Atomic Theory
TRUE All matter is made up of atoms. Atoms are the smallest fundamental units of matter. All elements consist of atoms which are indivisible & indestructible. All atoms of the same element are identical in size, shape & mass. Atoms of different elements are different in size, shape, & mass. FALSE Nuclear reactions FALSE Isotopes TRUE

14 Dalton’s Atomic Theory
TRUE All matter is made up of atoms. Atoms are the smallest fundamental units of matter. All elements consist of atoms which are indivisible & indestructible. All atoms of the same element are identical in size, shape & mass. Atoms of different elements are different in size, shape, & mass. In a chemical reaction, atoms are rearranged, never created nor destroyed & they combine in whole number ratios. FALSE FALSE TRUE

15 Dalton’s Atomic Theory
TRUE All matter is made up of atoms. Atoms are the smallest fundamental units of matter. All elements consist of atoms which are indivisible & indestructible. All atoms of the same element are identical in size, shape & mass. Atoms of different elements are different in size, shape, & mass. In a chemical reaction, atoms are rearranged, never created nor destroyed & they combine in whole number ratios. FALSE FALSE TRUE TRUE

16 Dalton’s Atomic Model

17 Modern Atomic Theory (MAT) Developing
1839 Michael Faraday (English)- Atomic structure might be related to electricity…it might have a charge. Ben Franklin (English)- 2 types of charges Positive (later proton) Negative (later electron)

18 Problem with Dalton’s Atom Model?
Lacks subatomic particles…

19 Modern Atomic Theory (MAT) Developing
1897 JJ Thomson (English)- Cathode Ray Tube Experiment link

20 Thomson’s Plum-Pudding Model
+ - + Protons & Electrons Lots of empty space

21 Problem with Plum-Pudding Model?
+ - + - + + and - attract

22 Modern Atomic Theory (MAT) Developing
1909 Ernest Rutherford (English) Gold Foil Experiment link

23 Modern Atomic Theory (MAT) Developing
The Results & The Explanation Most of positive charges passed through because the atom is mostly empty space. Some of the positive charges deflected because the atom contains some positive charge. Some of positive charges deflected straight back because there is a concentrated area of positive charge (nucleus).

24 Rutherford’s Atomic Model
_ +++ ++++ Nucleus- Contains Protons Electrons surround nucleus Lots of empty space

25 Problem with Rutherford’s Model?
+++ ++++ _ _ +++ ++++ + and - attract Why? Why? Why? Don't the electrons get pulled to the center where the protons are?

26 Modern Atomic Theory (MAT) Developing
1913 Niels Bohr (American)- Solar System Model- Electrons are like planets that orbit the nucleus link

27 Problem with Solar System Model?
Scientists found this model failed for atoms other than Hydrogen because it couldn’t predict the energy levels of electrons in atoms with more than one electron.

28 Modern Atomic Theory (MAT) Developing
1924 Louis de Broglie (French physicist)- Wave and particle Model- 1926 Werner Heisenberg (German physicist)- Uncertainty Principle

29 Modern Atomic Theory (MAT) Developing
1926 Erwin Schrodinger- (Austrian Physicist) Charge Cloud Model- Basic Parts of the Atom Nucleus Electron Cloud link

30 ATOM COMPOSITION The atom is mostly empty space
protons and neutrons in the nucleus. the number of electrons is equal to the number of protons. electrons in space around the nucleus. extremely small. One teaspoon of water has 3 times as many atoms as the Atlantic Ocean has teaspoons of water.

31 Nucleus is Very Massive
Protons - Positive Charge Neutrons - Neutral Electrons - Negative


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