GREAT SCIENTISTS OF WORLD -NIELS BOHR

 Niels Bohr was one of the foremost scientists of modern physics, best known for his substantial contributions to quantum theory and his Nobel Prize-winning research on the structure of atoms. Born in Copenhagen in 1885 to well-educated parents, Bohr became interested in physics at a young age

In 1913, Niels Bohr proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in certain well defined quantities. Electrons should move around the nucleus but only in prescribed orbits. When jumping from one orbit to another with lower energy, a light quantum is emitted.

 

Bohr Model has some inaccuracies, but it's still used because of its simple approach to atomic theory. The Bohr model was also the first atomic model to incorporate quantum theory, meaning that it's the predecessor of today's more accurate quantum-mechanical models.

  Bohr proposed his quantized shell model of the atom to explain how electrons can have stable orbits around the nucleus. ... To remedy the stability problem, Bohr modified the Rutherford model by requiring that the electrons move in orbits of fixed size and energy.

 The Bohr model can be summarized by the following four principles: Electrons occupy only certain orbits around the nucleus. Those orbits are stable and are called "stationary" orbits. Each orbit has an energy associated with it.
Electrons orbit the nucleus in orbits that have a set size and energy. The energy of the orbit is related to its size. The lowest energy is found in the smallest orbit. Radiation is absorbed or emitted when an electron moves from one orbit to another.

Niels Bohr suggested that electrons in an atom were restricted to specific orbits and has a fixed boundaries around the atom's nucleus. ... In Bohr's model, electrons can only exist in certain orbits and thus, can only have certain energies. As a result,  the energies of the electrons are quantized.

  Bohr's theory could explain why atoms emitted light in fixed wavelengths.

Drawbacks of Bohr's Model:

It was primarily for hydrogen atom. It couldn't elaborate spectra of multi-electron atoms. Wave nature of electron was not justified by the model (i It didn't illustrated molecules making process of chemical reactions.The main problem with Bohr's model is that it works very well for atoms with only one electron, like H or He+, but not at all for multi-electron atoms.

 The two weaknesses of bohr's atomic model are : 1) the path of electron around nucleus is considered to be circular of definite radius but in reality it can be at any distance from the nucleus. 2) the model is based on spectra of atoms and newton's laws of motion which are not applicable to microscopic particles.

 Niels Bohr changed our daily lives because even though Bohr worked on the atomic bomb. Bohr soon noticed that this could cause some serious damage to people so Bohr quickly switched from working on the atomic bomb to promoting atomic energy in a more useful and peaceful way.

Bohr's greatest contribution to modern physics was the atomic model. The Bohr model shows the atom as a small, positively charged nucleus surrounded by orbiting electrons.

The life of Niels Bohr was important   for science. Bohr   made important contributions to the understanding of the structure and energy of the atom, for which he was awarded the Nobel Prize. He helped clarify several problems with quantum physics, including complementarity and fission.

 Niels Bohr applied his atomic theory to the periodic table of elements. He showed that chemical properties of an element resulted mainly from the behavior of valence electrons, the electrons occupying the highest stable orbit.Also, Bohr predicted that the undiscovered atomic element 72 would resemble zirconium.

The Bohr model or Rutherford–Bohr model, presented by Niels Bohr and Ernest Rutherford in 1913, is a system consisting of a small, dense nucleus surrounded by orbiting electrons—similar to the structure of the Solar System, but with attraction provided by electrostatic forces in place of gravity.

 On August 1, 1912, Bohr married Margrethe Nørlund, and the marriage proved a particularly happy one. Throughout his life, Margrethe was his most-trusted adviser.Bohr and Margrethe had six sons.

On November 18, 1962, Niels Bohr died in Copenhagen, Denmark, reportedly due to heart failure.  This is the same city in which Niels Bohr was born on October 7, 1885.

 Niels Bohr