## Category: Atoms

## If Bohr’s quantisation postulate (angular momentum nh/2n) is a basic law of nature, it should be equally valid for the case of planetary motion also. Why then do we never speak of quantisation of orbits of planets around the sun?

## The total energy of an electron in the first excited state of the hydrogen atom is about -3.4 eV. (a) What is the kinetic energy of the electron in this state?

The total energy of an electron in the first excited state of the hydrogen atom is about -3.4 eV. (a) What is the kinetic energy of the electron in this state? (b) What is the potential energy of the electron Read More …

## Classically, an electron can be in any orbit around the nucleus of an atom. Then what determines the typical atomic size? Why is an atom not, say, thousand times bigger than its typical Size? The question had greatly puzzled Bohr before he arrived at his famous model of the atom that you have learnt in the text. To simulate what he might well have done before his discovery, let us play as follows with the basic constants of nature and see if we can get a quantity with the dimensions of length that is roughly equal to the known size of an atom ( 10-10 m).

Classically, an electron can be in any orbit around the nucleus of an atom. Then what determines the typical atomic size? Why is an atom not, say, thousand times bigger than its typical Size? The question had greatly puzzled Bohr before Read More …