Ncert Exercises & Solutions

2.26 An atom of an element contains 29 electrons and 35 neutrons. Deduce (i) the number of protons and (ii) the electronic configuration of the element.

(i) For an atom to be neutral, the number of protons is equal to the number of electrons.
$∴$ Number of protons in the atom of the given element = 29

(ii) The electronic configuration of the atom is $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 4 s^{2} 3 d^{10}$ .