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said matter is made of 4 elements(earth,air,fire and water).Those could mix together and make new substances.
ex. Volcanic Rock made of two parts of fire and one part of air. -
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said matter was made of small particles that cant be broken into smaller pieces.
He named them atoms which means invisible.So,different elements are made of different atoms.(It wasn't approved by socrates)
This theory wasn't accepted widely. -
Believed in Empedocles theory.
As he was a great influencer,the"four-element" theory was accepted for 2000 years. -
A group of philosophers,mystics,magicians and chemists did a lot of experiments to make gold from other metals such as iron and lead.
One of their achievements was coming up with chemical symbols for substances.
They created many lap tools like beakers,filters..etc.
They believed in the four element theory. -
Created a new for the term element.
An element in a pure substance that can't be chemically broken down into simpler substances.
He believed air is not an element but a mixture. -
First one who managed to isolate oxygen scientifically. -
Concluded that air must be a mixture of at least 2 gases,one of them was oxygen. -
Made an experiment and mixed a metal with acid.
(He got a flammable gas that was lighter than air."He did not know it was hydrogen"
He found that it could burn in oxygen and producing water.
-Till that time scholars thought water was an element. -
John had a theory of the reason behind difference between elements and non-elements.
He stated that "all matters are made up of atoms.Each element has its own atoms with particular mass.
He also said that compounds are formed when different atoms join together to form molecules.
Atoms cannot be invented,ruined or broken down in chemical changes. -
Michael found that electric current could do chemical changes in some compounds in solution.The atoms could obtain electric charges and produce charged atoms called ions.
Matter have negative and positive charges .
Opposite charges attract and like charges repel.
atoms join together to form molecules because of electrical attraction. -
Developed the atomic model.
He discovered electrons(negative particles)
He also did an experiment with beams of much positive particles.
The new model was called "raisin-bun"
.Atomics have particles called electrons
.Electrons are negative charged and smaller in mass
.The rest of the atom in positive charge
.The electrons are inserted in their sphere,resulting neutral atoms. -
He modeled the atom as a positive sphere surrounded by negative electrons. -
He designed an experiment yo test Thomson and Nagaoka's model.
He came up with a new model"Nuclear Model"
An atom has a tiny positive core called nucleus.
The nucleus is surrounded by rapidly moving negative electrons