PRESENTATION OUTLINE
Democritus
The atomic theory stated that “The universe is composed of two elements: the atoms and the void in which they exist and move.”
Antoine Lavoisier
Antoine Lavoisier proved the law of conservation of mass around the year 1789.
The law of conservation of mass states that: Mass cannot be created or destroyed. The mass of the reactants must equal the mass of the products.
He also proved that oxygen and hydrogen when combined form water.
John Daltom
John Dalton proposed that all matter is composed of very small things which he called atoms.
Law of conservation of Mass
The Law of Conservation of Mass states that matter can be changed from one form into another, mixtures can be separated or made, and pure substances can be decomposed, but the total amount of mass remains constant.
Dalton's atomic theory
Daltons atomic theory states that all matter is made of atoms. Atoms are indivisible and indestructible. All atoms of a given element are identical in mass and properties. Compounds are formed by a combination of two or more different kinds of atoms and A chemical reaction is a rearrangement of atoms.
Dmitri Mendeleev
Mendeleev is best known for his work on the periodic table; arranging the 63 known elements into a Periodic Table based on atomic mass, which he published in Principles of Chemistry.
J.J. Thomson
Thomson said that no matter where matter came from, it contained particles that were the same and are smaller than the atoms that matter is formed from.
Plum pudding
Discovered electrons
Gold foil project
This experiment was determined to find out the structure of an atom. It was preformed by Rutherford.
Cathode Ray Tube Experiment
This is vacuum-sealed tube with a cathode and anode on one end that creates a beam of electrons travelling towards the other end of the tube. By J.J Thompson
Plum pudding atomic model
Thomson had discovered that atoms are composite objects, made of pieces with positive and negative charge, and that the negatively charged electrons within the atom were very small compared to the entire atom. He proposed that atoms have structure like to a plum pudding, with negatively charged electrons embedded in a positively charged substrate.
Robert Millikan
Millikan worked on an oil-drop experiment in which he measured the charge on a single electron.
Ernest Rutherford
Rutherford discovered that atoms not independent, they are controlled by a nucleus. He noticed that the majority of an atom's mass is concentrated at a point in the center where the nucleus was located. He also discovered there is something smaller than an atom.
Rutherford Model
This model was first modern concept of atomic structure. He said that all of the positive charge and most of the mass of the atom are contained in a compact nucleus; a number of electrons occupy the rest of the volume of the atom and make the positive charge.
Bohrs planetary model
Bohr discovered that electrons orbit the nucleus at set distances. When an electron changes orbits, it does so in a sudden leap. The energy difference between the initial and final orbit is emitted by the atom in bundles of electromagnetic radiation called photons.
Neils Bohr
The Bohr model shows the atom as a small, positively charged nucleus surrounded by orbiting electrons.
Quantum mechanical model
Quantum mechanical model is a wave–particle duality of energy and matter and the uncertainty principle provide a unified view of the behavior of photons, electrons, and other atomic-scale objects.
Henry Moseley
Moseley invented the atomic number on the periodic table to make calculating and recognizing things easier.
Electron cloud model
The electron cloud model is an atom model wherein electrons are no longer depicted as particles moving around the nucleus in a fixed orbit. It was created by Erwin Schrodinger.
Erwin Schrödinger
Schrödinger used mathematical equations to describe the likelihood of finding an electron in a certain position. This atomic model is known as the quantum mechanical model of the atom.
James Chadwick
James Chadwick discovered the neutron of the atom by looking at the atomic number and the number of protons.
