Chemestry

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THE ATOMIC MODEL BY ERWIN SHRÖDIINGER

Schrodinger was widely known for his contributions to the quantum mechanics. He founded the wave mechanics and developed the Schrodinger Equation, for which he received a Nobel Prize. This equation too many physicist is singly the most important contribution to theoretical physics, including wave mechanics theory. These discoveries and concepts about wave mechanics have been vital in modern understandings of subatomic particles and the movement and behavior of light. He also made pioneering advancements in the fields of genetic study and quantum physics.

Following up on de Broglie's ideas, physicist Peter Debye made an offhand comment that if particles behaved as waves, they should satisfy some sort of wave equation. Inspired by Debye's remark, Schrödinger decided to find a proper 3-dimensional wave equation for the electron. He was guided by William R. Hamilton's analogy between mechanics and optics, encoded in the observation that the zero the trajectories of light rays become sharp tracks that obey Fermat's principle, an analog of the principle of least action.

ATOMIC MODEL BY ERNEST RUTHERFORD

In 1911, Rutherford proposed a new model for the atom. His experiments were the first to show that the atom must consist of a very tiny positively charged nucleus surrounded by negatively charged electrons. (For the record, Rutherford also discovered and named alpha, beta and gamma radiation.) He was the first man to split the atom.

After Rutherford's discovery, scientists started to realize that the atom is not ultimately a single particle, but is made up of far smaller subatomic particles. Subsequent research determined the exact atomic structure which led to Rutherford's gold foil experiment. Scientists eventually discovered that atoms have a positively-charged nucleus (with an exact atomic number of charges) in the center, with a radius of about 1.2 x 10−15 meters x [Atomic Mass Number]1/3. Electrons were found to be even smaller.

Rutherford presented his own physical model for subatomic structure, as an interpretation for the unexpected experimental results. In it, the atom is made up of a central charge (this is the modern atomic nucleus, though Rutherford did not use the term "nucleus" in his paper) surrounded by a cloud of (presumably) orbiting electrons. In this May 1911 paper, Rutherford only commits himself to a small central region of very high positive or negative charge in the atom.

It was rejected because: According to classical theory, electrons being the charged particles should release or emit energy continuously and they should ultimately fall into the nucleus. If the electrons emit energy continuously, they should form a continuous spectrum but in fact, line spectrum was observed.

THE ATOMIC MODEL BY J.J. THOMSON

His atomic theory identified that electrons inside an atom could show, meaning that atoms were not invisible.

Thomson suggested that the model of an atom as a sphere of positively charged matter with negatively charged electrons surrounding them. He stated that electrons were positioned by electrostatic forces.

After the discovery of the electron and proton as subatomic particles J.J. Thomson had started to discover atomic theory that gives complete explanation of atomic structure. According to Thomson protons are embed in the atoms like a water melon and electrons are present in atoms to make the atom electrically neutral. his discovered atomic theory was not able to explain the atomic structure properly.

If a gas sample is introduced into the region between two charged plates, a current flow can be observed, suggesting that the atoms have been broken down into charged constituents. The source of these charged particles is a heated cathode that, in fact, causes the atoms of the sample to ionize. These were known as cathode rays. In 1897, Thomson set out to prove that the cathode rays produced from the cathode were actually a stream of negatively charged particles called electrons.

J.J. Thomson was "wrong" assumed that the electrons and the positive charge of an atom were all one uniform blob of because he matter.

THE ATOMIC MODEL BY NIELS BOHR

In 1913, Bohr’s model of atomic structure was published which became the basis of the famous quantum theory.In1916, Niels Bohr became a Professor at the University of Copenhagen and later founded the Institute of Theoretical Physics in 1921. Bohr’s institute became headquarter for theoretical physicists and most of the best known physicists contributed there.

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