4.1 Notes
- 1. Studying Atoms Ancient Greek Models Dalton’s Theory Thomson’s Model Rutherford’s Theory
- 2. Ancient Greek Models Atoms cannot be seen even with a microscope Atomos in Greek means uncut Democritus- the smallest indivisible particle of matter is an atom
- 3. Dalton’s Theory The ratio’s of the masses in a compound are constant Dalton proposed the theory that all matter is made up of individual particles called atoms
- 4. All elements are composed of atoms All atoms of the same element have the same mass Compounds contain atoms of more than one element Atoms in a particular compound always combine in the same way Dalton’s Theory
- 5. Thomson’s Model Charges attract or repel - like charges repel, -opposite charges attract Thomson was able to bend a beam of charged particles using a magnet His experiments provided the first evidence of subatomic particles
- 6. Chocolate chip model of an atom- although neutral Thomson’s experiment displayed charges in atoms. The chocolate chips represent the negative portion of an atom and the surrounding the positive portion- the cookie Thomson’s Model Thomson model
- 7. Rutherford’s Atomic Theory Alpha particles are positively charge particles Using gold foil he found that particles where deflected differently than expected
- 8. Positive charge in an atom concentrated in central area called the nucleus The relative size of the nucleus would equal the size of a marble in the center of a football field Rutherford’s Atomic Theory