Chapter 4.1 An Atomic Model of Matter The Greek Model Dalton’s model Thompson’s model Rutherford’s model Bohr’s model Modern model How Elements Are Formed Clip http://www.youtube.com/watch?v=uKqvjEE0wFg
The Greek model Democritus said that matter could not be divided into smaller and smaller pieces forever. He proposed the atom or Atomos meaning –not divisible These philosophers were called Atomist
Indirect Evidence The atomist only had indirect evidence they did not have microscopes… This is evidence that you get without seeing or touching it
Dalton’s Model Daltons proposed a 4 part theory about atoms 1. All elements are Composed of atoms 2. Atoms of the same element are alike 3.Atoms of different elements are different 4. Compounds are formed by the joining of 2 or more elements
Thomson’s Model According to Thomson the atom was made of a pudding like positively charged material throughout which negatively charged electrons were scattered like plums in pudding.
Rutherford’s Model Rutherford said that the positive particles were contained in the nucleus and the negative charged particles were scattered outside
The Gold Foil Experiment Clip http://www.dnatube.com/video/2811/Nucleus-of-an-atom
Bohr’s Model Bohr stated that electrons orbited around the nucleus like planets around the sun and each orbit was a different energy level.
The Modern Model Electrons are behaving more like waves than planets and they vibrate back and forth. They are like bees around a hive. History Timeline of the Atom
Building blocks of molecules Atoms are the smallest part of an element that acts like that element Atoms are composed of 3 smaller particles: Protons, electrons and neutrons.
Democritus Modern
Modern Model of Atom