Answered

According to the electron-cloud model of the atom, an orbital is a
(1) circular path traveled by an electron around the nucleus
(2) spiral path traveled by an electron toward the nucleus
(3) region of the most probable proton location
(4) region of the most probable electron location



Answer :

According to the electron-cloud model of the atom, an orbital is a "region of the most probable electron location" In this mode, an electron can actually be in two places at once. 
PBCHEM

Answer : Option 4) Region of the most probable electron location.


Explanation : As per the electron cloud model of the atom, an orbital is a region where the probability of finding an electron is highest. According to this model which was used to identify the probable location of the electrons when they go around the nucleus of an atom.


This electron cloud model was different from the older Bohr atomic model by Niels Bohr.