BY Dhruv Rana, Miguel Rivas, Cristian Tapia

 More than 2000 years ago  Were from Greece  Aristole believed in four elements: Earth, Water, Wind, Fire  Democritus thought that matter was composed of small particles called “atoms”  They both used observation and inference to explain the existence of the world

 Discovered by European scientists  800 to 900 years ago  Their work contributed to what now is modern chemistry  They attempted to turn all objects possible into gold but failed to do so

 During 1808 in England  Explained why tiny particles named atoms could not be divided  Thought each element was composed of its own kind of atom and developed the atom theroy with this scientific research.

 During 1897 in England  Thompson discovered that the smaller particles of an atom that were negatively charged electrons  Thompson couldn’t find the positive charge in a atom but knew that it was neutrally charged.

 During 1911 in England  He was conducting an experiment to isolate the positive particles in an atom  His conclusion was that an atom was mostly empty space but had a dense central core  He didn’t know how to arrange positive and negative particle of an atom

 In 1913, in England  He proposed that electrons traveled in fixed patterns around the nucleus.  Scientist still use Bohr’s model today that show how many number of electrons are in a atom.  He conducted an experiment to show why electron did not get stuck into the nucleus.

THE ELECTRON TRAVELS AROUND THE NUCLEUS IN ROUND ORBIT. SCIENTIST CANNOT PREDICT WHERE THE ELECTRONS WILL BE IN ANY GIVEN TIME.