A) What are the postulates of Bohr's model of an atom?

(b) Show diagrammatically the electron distributions in Sodium, Lithium and Aluminium atoms

a) As I remember "the atomic spectra" of bohr

1 - Existence of a positively charged nuclei in the centre of the atom

2 - Number of negatively charged electrons = number of positive charges ported by the atom.

3 - Electrons navigate in fixed energy levels, with a high speed without gain or loose energy

4 - centrifugal force is in equilibrium with attraction force.

5 - The empty space between energy levels is forbidden for electrons.