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350
Philosopher Aristole
Philosopher Aristole also belived that the were four main elements (earth,air,fire and water). This was very imporant because Philsosher was a very important person. -
400
Particles and atoms
Democritus, suggested that matter was made up of tiny particle that could not be broken down further. -
450
Four elements of matter
A greek scholar named Empedocles proposed that matter was composed of four element earth, air, fire and water. When mixed togeter in different proprotions it would yield different substance. For example: Fire is a mixture of hotness and dryness. -
Robert Boyle
An english scientist, Robert Boyle did not belive in the four-element model. He went on to make his own diffenition for a element " a pure substance that cannot be chemically broken down into simpler substacnes. He also belived that air was not a element. -
Joseph Priestley
Jsoeph Priestley was the first person to isolate oxygen scientifically, But he did not know that oxygen was a element. In concludion Lavoisier stated that air must be a mixture of at least two gases, one of which is oxygen. -
Daltons modified verison
Dalton's atomic model did not explain why, on a dry winter day, you get a spark when you touch a metal doornob. In 1831, Michael Faraday found that electric currents could cause chemic changes in some compounds in solution Daltons modified verison was:
- Matter must contain positive and negative charges.
- Opposite charges attract and like charges repel.
- Atoms combine to form molecules because of electrical attractions between atoms. -
John Dalton's theory
By this stage in time it was pretty much accepted but everyone that matter was made up of four elements: two modles had come together. John Dalton Stated a theory with included
- All matter is made of atoms, which are particles too small to see with the human eye.
- Each element has its own kind of atom, with its own Particle mass.
- Compounds are created when atoms of different elements link to form molecules.
- Atoms cannot be created, destroyed, or subdivided in chemical changes -
J.J Thomson atomic model
Later on J.J Thomson revised the atomic model even further, to explain his discovery of very light negative particles, called electrons. His new model became known as the raisinbun model.
- Atoms contain particles called electrons.
- Electrons have a small mass and a negative charge.
- The rest of the atom is a sphere of positive charge.
-The electrons are embedded in this sphere, so that the resulting atoms are neutral or uncharged -
The nuclear model
Ernest Rutherford did a experiment to test Thomsons and Nagaoka's models. After the finishing his experiment Ernest decised to come up with a new model the nuclear model which included:
- An atom has a tiny, dense, positive core called the nucleus ( which deflected the alpha particles and contains protons)
- The nucleus is surrounded mostly be empty space, containing rapidly moving negative electrons ( though which the alpha particles passed unhindered). -
invention of Science tools
This time period was very important for science and experiments. During this time many laboratories were made and tools we still use this everyday such as beakers, filters, stirring rods and distillation apparatus.
