explain Bohr's model of an atom.
Answers
Neils Bohr gave atomic model in 1913.The main points of this model are:
1) An atom consists of a central positive part called the nucleus which contains all the protons and neutrons.
2) Electrons which are present outside the nucleus revolve around the nucleus in definite circular paths called orbits or shells.
3) Each orbit has a fixed energy and the orbitals are represented by the symbols K, L,M, N etc or by the numbers 1,2,3 …
4) Each orbit can accommodate not more than a fixed number of electrons.
5) Electrons moving in the same orbit donot lose or gain energy.
6) Electrons lose energy on jumping from a higher orbit to lower one and vice-versa.
Niels Bohr proposed the Bohr Model of the Atom in 1915. Because the Bohr Model is a modification of the earlier Rutherford Model, some people call Bohr's Model the Rutherford-Bohr Model. The modern model of the atom is based on quantum mechanics. The Bohr Model contains some errors, but it is important because it describes most of the accepted features of atomic theory without all of the high-level math of the modern version. Unlike earlier models, the Bohr Model explains the Rydberg formula for the spectral emission lines of atomic hydrogen.
The Bohr Model is a planetary model in which the negatively-charged electrons orbit a small, positively-charged nucleus similar to the planets orbiting the Sun (except that the orbits are not planar). The gravitational force of the solar system is mathematically akin to the Coulomb (electrical) force between the positively-charged nucleus and the negatively-charged electrons.
Main Points of the Bohr Model
1. Electrons orbit the nucleus in orbits that have a set size and energy.
2. The energy of the orbit is related to its size. The lowest energy is found in the smallest orbit.
3. Radiation is absorbed or emitted when an electron moves from one orbit to another.