An element has atomic number 13 and an atomic mass of 27.(a) How many electrons are there in each atom of the element?(b) How are these electrons distributed in the various energy levels?

(a) The atomic number of a given element is 13 i.e. the number of protons in an atom. Thus, there is 13 e^- in each atom of the given element because, in a neutral atom, the number of protons is equal to the number of electrons.

(b) Electronic configuration of given element (2,8,3)  is