The History of The Atom
- Created by: catherinelovesxmen
- Created on: 19-09-19 10:00
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- History of The Atom
- Dalton's Model
- 1870s- One of the first developments of the atom.
- Dalton carried experiments on how elements combined.
- Model was a small, indestructible sphere.
- All atoms in an element are the same.
- Atoms in one element are different from atoms in other elements.
- J.J Thomson
- 1897- investigated rays given out by cathode rays.
- Cathode rays are hot metals.
- Cathode rays are made of particles that have less than one-thousandth of the mass of a H atom.
- Found a particle called an electron, came from induse an atom.
- Charge of an electron is negative.
- Atoms have no electrical charge, they're neutral.
- 1904- Plum pudding model.
- Thought atoms consisted of a positive mass with negative electrons embedded.
- Did not know what positive mass was made out of.
- Solid/cloud
- 1897- investigated rays given out by cathode rays.
- Rutherford
- 1899- Some materials emit particles.
- These were called alpha particles.
- Alpha particles have a positive charge.
- Decided to fire alpha particles at a piece of gold foil.
- Geiger and Marsden helped with experiment.
- Alpha particle source in a lead box with narrow hole.
- Alpha particles were fired out at gold foil.
- Some alpha particles bounced back.
- This was because they had hit the nucleus.
- Some alpha particles bounced back.
- Alpha particles were fired out at gold foil.
- Discovered that atoms have a nucleus.
- Nucleus holds the mass of the atom.
- Later scientists discovered that the mass contained protons and neutrons.
- 1899- Some materials emit particles.
- Bohr Model
- 1913- Electrons can only move around fixed orbits.
- These are electron shells.
- 1913- Electrons can only move around fixed orbits.
- Things to Remember
- Atom is 10x10 power of - 10, standard form.
- PEN: Protons, Electrons and Neutrons.
- Length of a molecule: 10x 10 to the power of -8.
- Dalton's Model
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