Upload
alan-flynn
View
18
Download
1
Tags:
Embed Size (px)
DESCRIPTION
Make this table in your iSN. How did we figure out these very, very, small particles existed? As we go, 1) check the boxes that apply in your table 2) draw a diagram for each model. Atom Videos: Nanotechnology. How small are atoms? http://www.firecold.com/videos/the-real-size-of-an- atom. - PowerPoint PPT Presentation
Citation preview
Make this table in your iSNAtoms cannot be divided
Electron Nucleus Electrons orbit nucleus
Electrons in Energy levels
Electron Cloud
Greek Dalton Thomson Rutherford X X XBohr X X X XShrodinger and Heisinberg
x x x x x
How did we figure out these very, very, small particles existed?
As we go, 1) check the boxes that apply in your table2) draw a diagram for each model.
Atom Videos: Nanotechnology
How small are atoms?
http://www.firecold.com/videos/the-real-size-of-an-atom
KEY POINTS Atoms are so small it is difficult to imagine.
Atoms are mostly empty space. Drawings of the atom don’t show his because otherwise the nucleus would not be visible.
The nucleus is very dense!
Which is smaller, a cell or an atom? Also…they both have a nucleus?
http://learn.genetics.utah.edu/content/begin/cells/scale/
Nucleus = the center
Nucleus of a cell contains DNA which contains atoms.
Everything else in the cell is made of atoms.
The nucleus of an atom contains protons and neutrons
An atom is 1,000,000 times smaller than a cell!
Greek Model
Democritis- Greek philosopher
400 BC Idea of ‘atomos’ – at some
point, matter cannot be further divided
Based on philosophy, not science
This theory was ignored and forgotten for more than 2000 years!
Dalton’s Theory- 1803
• All elements are made of atoms. Atoms can’t be divided or destroyed.
• Atoms of the same element are exactly alike.
• Atoms of different elements are different.
• Compounds are formed by the joining of atoms of two or more elements.
Thomson Model- 1897
• Plum Pudding model.
• Atoms were made from a positively charged substance with negatively charged electrons scattered about, like raisins in a pudding.
Rutherford
• ****positively charged particles were contained
in the nucleus.
• negatively charged particles were scattered outside the nucleus around the atom’s edge.
http://www.youtube.com/watch?v=bSEOOMs5VNU
http://www.youtube.com/watch?v=hJs6PcgqMPA&feature=related
Gold Foil Experiment
Bohr Model- 1913• The electrons
move in energy levels
• located at specific distances from the nucleus.
1925- Electron Cloud Model
it is impossible to determine the exact location of an electron, but we can estimate probabilities.
More complex than energy levels. According to the modern atomic model, at atom has
a small positively charged nucleus surrounded by a large cloud-like region of electrons
What does your table look like?Atoms are cannot be divided
Electron Nucleus Electrons orbit nucleus
Electrons in Energy levels
Electron Cloud
Greek XDalton XThomson XRutherford X X XBohr X X X XShrodinger and Heisinberg
x x x x x
We have seen several atomic ‘models.’
What is the scientific definition of a model? When would you use a model?
Can we think of other examples of models?
The Electron Cloud model is the newest model.
1) Does that make it the ‘best.’
2) Why is it useful to look at the other models?
Want to learn more?Search terms for your investigation:
Democritus – Billiard ball model John Dalton JJ. Thomson – plum pudding modelErnest Rutherford- Gold Foil Experiment
Inside of protons and neutrons- Quarks, Gluons
Details on experiments- Glencoe book pg 62-74
How is an atom held together?
http://learningcenter.nsta.org/lcms/default.aspx?a=so&gid=1162&tid=372&soid=72
Then…how is the Nucleus Held Together?
Then…how is the Nucleus Held Together?
In sum, the force holding the nucleus together is stronger than the repulsive force of the positively charged protons.