CI and Ar are isoelectronic. Which is larger in size? Why? Without more information a question on size can not be answered. O The chloride ion, Cl- is smaller than the Ar atom because although they have the same number of electrons the chloride ion has 1 less proton. O None of these O The chloride ion, Cl- is equal in size to the Ar atom because they have the same number of electrons. The chloride ion, Cl- is larger than the Ar atom because although they have the same number of electrons the chloride ion has 1 less proton