ATOM
MADE BY:-GROUP-1{CHEMISTRY}
About The Scientist…….
HE was a Danish physicist who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in
Physics in 1922. Bohr was also a philosopher and a promoter of scientific research.
He was born in Copenhagen on 7 October 1885.
He wrote many books like the theory of spectra and atomic constitution, atomic theory and the description of nature.
NEILS BOHR (1885-1962)
His model of atom….
Bohar’s model of atom can be described as follows: An atom is made up of three particles-electrons, protons and neutrons. The protons and neutrons are located in a small nucleus at the centre of the atom.
The electrons revolve rapidly round the nucleus in fixed circular paths called energy levels or shells.
There is a limit to the number of electrons which each energy level can hold.
Each energy level is associated with fixed amount of energy.
There is no change in the energy of electrons as long as they keep revolving in the same energy level, and the atom remains stable.
Postulates….
In order to overcome the objections raised against
Rutherford’s model of atom,Neils
Bohr put forward the following postulates:Only certain special orbits known as discrete orbits of electrons are allowed inside the atom.
While revolving in discrete orbits the electrons do not radiate energy.
Difference between Rutherford’s and
Bohar’s model of atom..
In Rutherford's model of atom the nucleus is present at the centre of atoms and electrons reside outside the nucleus and revolve around the nucleus In well defined orbits.
The size of the nucleus is very small in comparison to the size of an atom.
In bohr’s model of atom the nucleus is present at the centre of atoms and electrons reside outside the nucleus and revolve around the nucleus in well defined orbits. The electrons do not radiate energy.
The size of nucleus is very