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500 BCE
The Alchemists
In 500 bc the Alchemists layed down the foundation of the periodic table we use today. They broke down the the element composition of the 4 basic elements. -
450 BCE
Democritus
He made the theory that all matter is made up of invisible particles (atoms). -
428 BCE
Plato
He believed that the atoms of matter must come from the 5 solids. -
Robert Boyle
Robert Boyle was the one who created Boyles Law he discovered that the volume of the gas is decreased the pressure increases proportionally he was also known for his law gases. -
Antoine Lavoisier
He discovered the atomic model and he found out that the total mass of products and reactants in a chemical reaction is always the same, this led to the theory of the law of conservation of mass. -
John Dalton
John Dalton created the theory that all matter is composed of atoms which are indivisible, the second part of his theory was that all atoms of a given element are identical in mass and proportions -
Billiard Ball Model
Dalton created this model. He thought that atoms were the smallest particles of matter so he thought of them as solid hard spheres like billiard (pool) balls. -
amedeo avogadro
He discovered the weight of atoms in the form of gas. Avogadro’s law is a gas law and is also known as Avogadro’s hypothesis or Avogadro’s principle. It says that the total number of molecules or atoms of a gas is directly proportional to the volume that the gas immerses at a constant temperature and pressure. -
Dmitri Mendeleev
He created the periodic table. -
JJ Thompson
He discovered that atoms have negative electrons and that electrons are separated in a uniform positive charge. -
Plum Pudding Model
This model was proposed by JJ Thompson this model shows that the atom is a spear of a positive charge and negatively charged electrons. They are on the total positive charge the electrons are like plums and pudding. -
Pierre and Marie Curie
They came up with the theory that elements decay over time and that elements give off radiation. -
Albert Einstein
he proved that atoms were real, he proved this by using math. -
Robert Millikan
He measured the charge of an electron using oil droplets. -
Ernest Rutherford
He believed that his nucleus theory was that positive electrons were only in the nucleus and he said that most of an atom is empty space. -
Neils Bohr
he proposed a theory for the hydrogen atom and it said electrons move around the nucleus but only in prescribed orbits and if the electron goes down one ring it sneds out a radiation. -
Solar System Model
This model is showing how an atom is the main big positive entity it is showing the nucleus represting the sun and orbiting around it is the negative entities (electrons/planets). -
Henry G. J. Mosely
He created the theory that there is no certain amount of protons (atomic number). He used math to fill in the rest of the periodic table -
Erwin Schrodinger
He discovered wave mechanics which then led him to discover quantum mechanics. -
Electron Cloud Model
Erwin Schrodinger created this model. This model is of an atom and the atom includes a small but massive nucleus surrounded by a cloud of fast-moving electrons. -
Werner Heisenberg
He formulated the quantum mechanics in terms of the matrices. -
James Chadwich
He discovered the neutron and he also said there was no charge in the neutrons.