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Democritus
He proposed a model of the atom that said matter is made of tiny, hard, indestrutable particles called atoms -
Antoine Lavosier
He recognized and named oxygen and hydrogen. He also showed the role oxygen plays in combustion. Also wrote the first extensive list of elements and predicted the exsistence of silicon -
John Dalton
He came up with Daltons Atomic Theory proposing all matter is made up of atoms and that atoms cant be destroyed of divided into smaller particles. -
Daltons Atomic Theory
Created by John Dalton to differenciate elements and compounds
-All matter is made up of samll particles
-atoms cannot be created, destroyed, or divided
-all atoms of the same element are identical in mass and size -
Dmitri Mendeleev
He created his own version of the periodic table of elements and used it to discover new elements and correct some of the previously disacoverd elements -
J.J. Thomson
He showed that rays emitted from negatively charged cathodes were made up of negatively charged particles that came from inside atoms, known as electrons. The first sub atomic particles discoverewd -
Cathode Ray Tube
Used by Joseph John Thomson to discover electrons. The tube emitted rays of negatively charged cathodes which were made up of negatively charged particles which showed us electrons -
Erwin Schrodinger
A physist who developed many results in the field of quantum theory. -
Plum Pudding Model
Created by J.J. Thomson as his own version of the atom. Electrons scattered about that are surrounded by a positive mass. -
Rutherford Model
Ernest Rutherfords model of the atom proposed that the nucleus is found at the center surrounded by prottrons and neutrons while electrons orbit aroubnd it -
Ernest Rutherford
He conducted the gold foil experiment and also proped his own version of the atom -
Gold Foil Experiment
Was used by Ernest Rutherford to discover the nucleus of an atom. He shot positively charged particles at a piece of gold foil and noted that some of the particles were bouncing back towards him. Coming to a conclusion that there was an extremely dense nucleus inside -
Quantum Mechanical Model
One of two models used today. The theory is based on mechanics and is used to explain sights made on complex atoms. The model uses complex shapes. -
Niels Bohr
He came up with an anwser as to why negatively charged electrons dont collide with the positively charged nucleus. He explained how the electrons were only able to occupy the energy levels -
Henry Moseley
He justified physical laws and the concept of the atomic number. He also developed Moseleys law by sorting chemical elements of the periodic table in a sensable order -
Bohr Planetary model
A model created by Niels Bohr to show why negatively charged electrons dont collide with the positively charged nucleus. SHowing that there are different energy levels within the atom -
Robert Millikan
He was a physist honoured for his works for the measurement of the elemetary electronic charge and his contribution toward the photoelectric effect. -
Electron Cloud
The electron cloud describes how electrons rotate around the nucleus of a atom. This was developed by Erwin Schrodinger and Werner Heisenberg -
James Chadwick
He was the first person to show experimentally that there was a neutrally charged particle also present in the necleus which is called the neutron.
