QUANTUM MECHANICAL MODEL OF THE ATOM PART 01
94.1 هزار بار بازدید -
10 سال پیش
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7 Active Technology Solutions Pvt.Ltd. is an educational 3D digital content provider for K-12. We also customise the content as per your requirement for companies platform providers colleges etc . 7 Active driving force "The Joy of Happy Learning" -- is what makes difference from other digital content providers. We consider Student needs, Lecturer needs and College needs in designing the 3D & 2D Animated Video Lectures. We are carrying a huge 3D Digital Library ready to use.
SUMMARY:
• Atoms are the building blocks of elements. They are the smallest parts of an element that chemically react.
• The first atomic theory, proposed by John Dalton in 1808, regarded atom as the ultimate indivisible particle of matter.
• Towards the end of the nineteenth century, it was proved experimentally that atoms are divisible and consist of three fundamental particles: electrons, protons and neutrons.
• The discovery of sub-atomic particles led to the proposal of various atomic models to explain the structure of atom.
• Thomson in 1898 proposed that an atom consists of uniform sphere of positive electricity with electrons embedded into it.
• This model in which mass of the atom is considered to be evenly spread over the atom was proved wrong by Rutherford's famous alpha-particle scattering experiment in 1909.
• Rutherford concluded that atom is made of a tiny positivelycharged nucleus, at its centre with electrons revolving around it in circular orbits.
• Rutherford model, which resembles the solar system, was no doubt an improvement over Thomson model but it could not account for the stability of the atom i.e., why the electron does not fall into the nucleus.
• Further, it was also silent about the electronic structure of atoms i.e., about the distribution and relative energies of electrons around the nucleus.
• The difficulties of the Rutherford model were overcome by Niels Bohr in 1913 in his model of the hydrogen atom.
• Bohr postulated that electron moves around the nucleus in circular orbits. Only certain orbits can exist and each orbit corresponds to a specific energy.
• Bohr calculated the energy of electron in various orbits and for each orbit predicted the distance between the electron and nucleus.
• Bohr model, though offering a satisfactory model for explaining the spectra of the hydrogen atom, could not explain the spectra of multi-electron atoms. The reason for this was soon discovered.
• In Bohr model, an electron is regarded as a charged particle moving in a well defined circular orbit about the nucleus. The wave character of the electron is ignored in Bohr's theory.
• An orbit is a clearly defined path and this path can completely be defined only if both the exact position and the exact velocity of the electron at the same time are known. This is not possible according to the Heisenberg uncertainty principle.
• Bohr model of the hydrogen atom, therefore, not only ignores the dual behaviour of electron but also contradicts Heisenberg uncertainty principle.
• Erwin Schrödinger, in 1926, proposed an equation called Schrödinger equation to describe the electron distributions in space and the allowed energy levels in atoms. This equation incorporates de Broglie's concept of wave-particle duality and is consistent with Heisenberg uncertainty principle.
http://www.7activestudio.com
[email protected]
http://www.7activemedical.com/
[email protected]
http://www.sciencetuts.com/
[email protected]
Contact: +91- 9700061777,
040-64501777 / 65864777
7 Active Technology Solutions Pvt.Ltd. is an educational 3D digital content provider for K-12. We also customise the content as per your requirement for companies platform providers colleges etc . 7 Active driving force "The Joy of Happy Learning" -- is what makes difference from other digital content providers. We consider Student needs, Lecturer needs and College needs in designing the 3D & 2D Animated Video Lectures. We are carrying a huge 3D Digital Library ready to use.
SUMMARY:
• Atoms are the building blocks of elements. They are the smallest parts of an element that chemically react.
• The first atomic theory, proposed by John Dalton in 1808, regarded atom as the ultimate indivisible particle of matter.
• Towards the end of the nineteenth century, it was proved experimentally that atoms are divisible and consist of three fundamental particles: electrons, protons and neutrons.
• The discovery of sub-atomic particles led to the proposal of various atomic models to explain the structure of atom.
• Thomson in 1898 proposed that an atom consists of uniform sphere of positive electricity with electrons embedded into it.
• This model in which mass of the atom is considered to be evenly spread over the atom was proved wrong by Rutherford's famous alpha-particle scattering experiment in 1909.
• Rutherford concluded that atom is made of a tiny positivelycharged nucleus, at its centre with electrons revolving around it in circular orbits.
• Rutherford model, which resembles the solar system, was no doubt an improvement over Thomson model but it could not account for the stability of the atom i.e., why the electron does not fall into the nucleus.
• Further, it was also silent about the electronic structure of atoms i.e., about the distribution and relative energies of electrons around the nucleus.
• The difficulties of the Rutherford model were overcome by Niels Bohr in 1913 in his model of the hydrogen atom.
• Bohr postulated that electron moves around the nucleus in circular orbits. Only certain orbits can exist and each orbit corresponds to a specific energy.
• Bohr calculated the energy of electron in various orbits and for each orbit predicted the distance between the electron and nucleus.
• Bohr model, though offering a satisfactory model for explaining the spectra of the hydrogen atom, could not explain the spectra of multi-electron atoms. The reason for this was soon discovered.
• In Bohr model, an electron is regarded as a charged particle moving in a well defined circular orbit about the nucleus. The wave character of the electron is ignored in Bohr's theory.
• An orbit is a clearly defined path and this path can completely be defined only if both the exact position and the exact velocity of the electron at the same time are known. This is not possible according to the Heisenberg uncertainty principle.
• Bohr model of the hydrogen atom, therefore, not only ignores the dual behaviour of electron but also contradicts Heisenberg uncertainty principle.
• Erwin Schrödinger, in 1926, proposed an equation called Schrödinger equation to describe the electron distributions in space and the allowed energy levels in atoms. This equation incorporates de Broglie's concept of wave-particle duality and is consistent with Heisenberg uncertainty principle.
10 سال پیش
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