Question

Discuss in detail the modern atomic theory, on how it evolved, and laws that led to its development in the present day form. Explain the structure of atom with respect to its components

Answer 1

Modern atomic theory:

the modern atomic theory was developed by a famous theoretical physicist Neils Bohr in the year 1913. this theory suggested that atom has a nucleus and which contains some particles and that electrons are found around this nucleus in concentric circles orbital arrangement. this model was initially taken from the arrangements of planets in our solar system and therefore it is also called planetary model.

there were 4 main principles which Bohr summarized his model in, and these are

1. Each electron has its certain path of motion around the nucleus and these are called orbitals and they are stationary or stable in nature.

2. There is a fixed energy which is associated with these orbitals and named them as E1 for the energy orbital near to nucleus and E2, next orbital and so on.

3. When an electron absorbs some energy in form of quanta of energy (photons) then it jumps from lower to higher orbits and Electron emits energy when an electron comes back to a lower orbital from a previous higher orbital.

4. The energy difference between any two orbitals can be used to calculate the frequency of light which was absorbed or emitted by an electron in its jumping motion.

Further, in 1932, neutrons (neutral in charge, thus the name) were discovered residing in the nucleus along with positively charged protons by physicist James Chadwick. and also according to modern atomic theory, the likelihood of an electron to be present in certain position was given by mathematical equations derived by Erwin Schrodinger in 1926.

Structure of atom is Protons and Neutrons are present together in the nucleus, where the proton is positively charged particle and neutron have no charge, thus giving the nucleus an overall positive charge. As described above. Electron orbits around this nucleus in certainly fixed orbitals depending on the particular energy of an electron. and change in electron can move it up or down in different orbitals.

Hope this clears your doubts about modern atomic theory.