Question

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.

Answer 1

An atom consists of protons, electrons & neutrons. A positive atom will contain a higher number of a proton(H⁺), a negative atom will have a higher number of electrons(e^-) & a neutral atom will contain the same number of protons & electrons. Therefore, 

(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

1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d¹⁰.

Hence, it is the electronic configuration of copper.