3.2 structure of atoms

2,185 views
1,946 views

Published on

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
2,185
On SlideShare
0
From Embeds
0
Number of Embeds
5
Actions
Shares
0
Downloads
0
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

3.2 structure of atoms

  1. 1. Structure of Atoms 3.2
  2. 2. Who discovered what? <ul><li>Thompson discovered electrons by using cathode ray tubes. </li></ul><ul><li>Rutherford discovered the nucleus . He also reasoned that it was positively charged. Gold foil experiments. </li></ul><ul><li>Chadwick discovered that a beam was not deflected in a magnetic field. The particles in the beam were named neutrons . </li></ul><ul><li>Read pages 79-82 </li></ul>
  3. 3. Subatomic Particles <ul><li>Proton + </li></ul><ul><ul><li>1.673 x 10 -27 kg. </li></ul></ul><ul><li>Neutron : no charge. </li></ul><ul><ul><li>1.675 x 10 -27 kg. </li></ul></ul><ul><li>Electron – </li></ul><ul><ul><li>9.109 x 10 -31 kg </li></ul></ul>
  4. 4. The AMU <ul><li>AMU stands for Atomic Mass Unit. </li></ul><ul><ul><li>Because the subatomic particles are so small the AMU was created to describe them. </li></ul></ul><ul><li>Proton = 1 AMU </li></ul><ul><li>Neutron = 1 AMU </li></ul><ul><li>Electron = 0 AMU </li></ul>
  5. 5. Atomic # & Atomic Mass <ul><li>The atomic # of an element is the same as the number of protons in one atom of that element. </li></ul><ul><li>The atomic mass of an element is the number of protons + the number of neutrons in one atom of that element. </li></ul>
  6. 6. The Periodic Table <ul><li>Symbols on the periodic table hold a lot of information. </li></ul><ul><li>Protons </li></ul><ul><li>Electrons </li></ul><ul><li>Mass </li></ul><ul><li>Element symbol </li></ul><ul><li>Neutrons? </li></ul>O 8 15.9994 2s 2 2p 4
  7. 7. C 6 12.011 S 16 32.066 Zn 30 65.39 H 1 1.007 Si 14 28.085 Li 3 6.941
  8. 8. Atomic Structure and Symbols <ul><li>It is common notation to write an element’s atomic number and mass number next to their symbol. </li></ul>Br 80 35
  9. 9. Isotopes <ul><li>Some atoms of the same element have different numbers of neutrons. They are called isotopes. </li></ul><ul><li>Example: </li></ul><ul><li>Both helium because they both have 2 protons. </li></ul>He He 4 3 2 2
  10. 10. Isotopes <ul><li>Elements and isotopes may also be written with the mass number followed by the name of the element. </li></ul><ul><li>Examples: </li></ul><ul><li>Oxygen-16 = normal oxygen, 8 protons, 8 neutrons. </li></ul><ul><li>Oxygen-17= isotope of oxygen, 8 protons, 9 neutrons </li></ul>

×