Chapter 4 Atoms and Elements
The Divisibility of Matter <ul><li>Infinitely divisible </li></ul><ul><ul><li>For any two points, there is always a point ...
Atomic Theory of Matter The belief that atoms are the fundamental building blocks of matter was reemerged in the early 19t...
Dalton’s Atomic Theory (1808) <ul><li>Each Element is composed of tiny, indestructible particles called atoms. </li></ul><...
Modern structure of the atom Subatomic Particle Symbol Electron e- Proton p Neutron n
The Discovery of Electrons <ul><li>http://highered.mcgrawhill.com/olcweb/cgi/pluginpop.cgi?it=swf::100%25::100%25::/sites/...
The Atom,1900: <ul><li>Thompson came up with a model called “Plum pudding” model.  In this model, he presented atoms as po...
Rutherford’s model of the atom http://highered.mcgraw-hill.com/sites/0072512644/student_view0/chapter2/animations_center.h...
In 1932 Chadwick observed that beryllium, when bombarded by alpha particles, released an unknown radiation that was neutra...
<ul><li>The nucleus contains protons and neutrons. </li></ul><ul><li>The nucleus is only about 10 -13  cm in diameter in c...
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The atomic history

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Take a tour through the atomic history.

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  • In this chapter we will be discussing the building blocks of substances: atoms
  • The notion of atomism started in the fifth century B.C.
  • The notion “atomism” wasn’t accepted really well in the fifth century until the 1800s when John Dalton presented a complete definition of the atom.
  • John Dalton presented atoms as the smallest building blocks of matter.
  • Experimentation showed that atoms are actually composed of smaller particles called subatomic particles. These include electrons, protons, and neutrons.
  • J. J Thompson discovered the electrons using cathode ray tubes.
  • Thomson explained the structure of the atoms in the “plum Pudding” model
  • Rutherford proved that the “plum pudding “model was wrong and he discovered the nucleus in the atom.
  • Chadwick discovered the entities that are responsible for the stability of the atom.
  • This the modern structureof the atom
  • The atomic history

    1. 1. Chapter 4 Atoms and Elements
    2. 2. The Divisibility of Matter <ul><li>Infinitely divisible </li></ul><ul><ul><li>For any two points, there is always a point between. </li></ul></ul><ul><li>Ultimate particle </li></ul><ul><ul><li>Upon division, eventually a particle is reached which can no longer be divided. </li></ul></ul>“ Nothing exists except atoms and empty space; everything else is opinion.” - Democritus 460–370 B.C.
    3. 3. Atomic Theory of Matter The belief that atoms are the fundamental building blocks of matter was reemerged in the early 19th century, championed by John Dalton.
    4. 4. Dalton’s Atomic Theory (1808) <ul><li>Each Element is composed of tiny, indestructible particles called atoms. </li></ul><ul><ul><li>Tiny, hard, indivisible, spheres. </li></ul></ul><ul><li>All atoms of an element are identical. </li></ul><ul><ul><li>They have the same mass, volume, and other physical and chemical properties. </li></ul></ul><ul><ul><li>So, atoms of different elements are different. </li></ul></ul><ul><ul><li>Every carbon atom is identical to every other carbon atom. They have the same chemical and physical properties. </li></ul></ul><ul><ul><li>However, carbon atoms are different from sulfur atoms. </li></ul></ul><ul><ul><ul><li>They have different chemical and physical properties. </li></ul></ul></ul><ul><li>3. Atoms combine in simple, whole-number ratios to form molecules of compounds. </li></ul>
    5. 5. Modern structure of the atom Subatomic Particle Symbol Electron e- Proton p Neutron n
    6. 6. The Discovery of Electrons <ul><li>http://highered.mcgrawhill.com/olcweb/cgi/pluginpop.cgi?it=swf::100%25::100%25::/sites/dl/free/0072512644/117354/01_Cathode_Ray_Tube.swf::Cathode%20Ray%20Tube - </li></ul>
    7. 7. The Atom,1900: <ul><li>Thompson came up with a model called “Plum pudding” model. In this model, he presented atoms as positive spheres of matter with negative electrons imbedded in them. </li></ul>
    8. 8. Rutherford’s model of the atom http://highered.mcgraw-hill.com/sites/0072512644/student_view0/chapter2/animations_center.html -
    9. 9. In 1932 Chadwick observed that beryllium, when bombarded by alpha particles, released an unknown radiation that was neutral. Chadwick interpreted this radiation as being composed of particles of mass approximately equal to that of the proton, but without electrical charge--neutrons. The Neutron
    10. 10. <ul><li>The nucleus contains protons and neutrons. </li></ul><ul><li>The nucleus is only about 10 -13 cm in diameter in comparison to 10 -8 cm as the atomic diameter </li></ul><ul><li>Protons identify the element </li></ul><ul><li>Electrons are responsible for the chemical behavior of the element </li></ul><ul><li>Neutrons stabilize the element </li></ul>Subatomic particle Mass (in amu) Charge (Coulombs) Number charge Electron 0.000548 – 1.602 x 10 -19 -1 Proton 1.00073 + 1.602 x 10 -19 +1 Neutron 1.00087 0 0

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