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John Dalton
Dalton’s atomic model is one of the fundamentals of physics and chemistry. This theory of atomic composition was hypothesized and partially confirmed by the English chemist and Physicist John Dalton. Dalton came with his Atomic theory as a result of his research into gases. He discovered that certain gases only could be combined in certain proportions even if two different compounds shared the same common element or group of elements. -
John Dalton Atomic Model
The results became the base of Dalton’s Atomic Laws or Model. These laws focus on 5 basic theorems. 1,st Pure Elements consist of particles called atoms. 2,atoms of an element are all the same for that element. That means gold is gold and oxygen is oxygen down to the last atom. 3, atoms of different elements can be told apart by their atomic weights. 4, atoms of elements unite to form chemical compounds. Finally, atoms can neither be created nor destroyed in chemical reactions. -
1873 William Crooke
He demonstrated that cathode rays travel in straight lines and produce phosphorescence and heat when they strike certain materials. He invented many devices to study the behaviour of cathode rays, but his theory of radiant matter, or a fourth state of matter, proved incorrect in many respects.Developed a better vacuum pump that allowed him to produce cathode-ray
tubes with a smaller residual gas pressure. -
Physict JJ Thomson
Discovered the electron in a series of experiments designed to study the nature of electric discharge in a high-vacuum cathode-ray tube.Found that cathode rays could be deflected by an electric field. Showed that cathode "rays" were actually particles. Found the charge to mass ratio of the particles to be approximately
108 Coulomb (C) per gram. Same charge to mass ratio regardless of metal used for cathode/anode or gas used to fill the tube. -
J. J. Thomson’s Model (Plum Pudding Atomic Model)
Thomson suggested a model of the atom as a sphere of positive matter in which electrons are positioned by electrostatic forces. His efforts to estimate the number of electrons in an atom from measurements of the scattering of light, X, beta, and gamma rays. Electron - (originally called corpuscles by Thompson) particles given off by the cathode; fundamental unit of negative electricity. Pudding Model: Matter is electrically neutral and electrons are much lighter than atoms. Model now incorrect! -
Quatum Mechanical Model
The quantum mechanical model is based on quantum theory, which says matter also has properties associated with waves. According to quantum theory, it’s impossible to know the exact position and momentum of an electron at the same time. This is known as the Uncertainty Principle.The quantum mechanical model of the atom uses complex shapes of orbitals volumes of space in which there is likely to be an electron. So, this model is based on probability rather then certainty. -
Rutherford Atomic Model
The model described the atom as a tiny, dense, positively charged core called a nucleus, in which nearly all the mass is concentrated, around which the light, negative constituents, called electrons, circulate at some distance, much like planets revolving around the Sun. The Rutherford atomic model has been alternatively called the nuclear atom, or the planetary model of the atom. -
Ernest Rutherford
Rutherford was the central figure in the study of radioactivity, and with his concept of the nuclear atom he led the exploration of nuclear physics. He won the Nobel Prize for Chemistry in 1908, was president of the Royal Society (1925–30) and the British Association for the Advancement of Science (1923) -
Bohr Model
the Bohr Model is probably familar as the "planetary model" of the atom In the Bohr Model the neutrons and protons occupy a nucleus, and the electrons orbit the nucleus much like planets orbiting the Sun. Shows the atom as small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus. -
Niels Bohr
He passed on to a study of the structure of atoms from Rutherford's discovery of the atomic nucleus. By using concepts from the Quantum Theory, which had slowly become a famous place in the science of theoretical physics, he succeeded in working out and presenting a picture of atomic structure that, with later improvements still serves as an clarification of the physical and chemical properties of the elements. -
James Chadwick
In 1932, Chadwick made a fundamental discovery in the domain of nuclear science: he proved the existence of neutrons. Sir James was knighted and one a nobel prize for his discovery of neutrons
