2. What is Chemistry? Chemistry is the study of matter (what scientists believe everything is made of) What does the word atom mean? The first meaning developed for the word atom was: cannot be divided This was DISPROVED! Many different theories for the atom Greek Dalton Thomson Rutherford Bohr
3. Greek philosophers Thought matter was composed of tiny particles You could take a piece of matter and keep cutting it into smaller pieces until you couldn’t any more
4. Dalton Used experiments in laboratories to combine his ideas with the Greek idea Realized that all matter is made of elements, which is a substance that cannot be broken down into more simple substances Atoms can be divided into smaller pieces and all atoms in an element are exactly the same Different elements = made of different atoms
5. Thomson Light particles benttowards a positive charge Negative and positive attract, so the particles in the light must be negatively charged! His idea was also that the electronswere scattered throughout the atom to neutralize the positive charges
6. Rutherford’s Gold Foil Experiment Created his own experiment to test Thomson’s ideas: Shot positively charged particles at a piece of gold foil BUT some particles bounced off at very sharp angles when they passed through the foil He thought there was a mass in the middle surrounded by mostly empty space
7. Rutherford continued… (blanks to fill in) A tiny, positive core Surrounded by a large cloud of tiny, randomly orbiting, negative electrons Orbitals Protons and neutrons
Editor's Notes
After SECOND POINT: and he thought most of the particles would move straight throughknew some would be deflected because of the positive charges
