How Do Isoelectronic Ions Compare in Size and Configuration?

[k-rod AP 2010]

Homework Statement

P^3-, S^2-, Mn⁷⁺ , Sc³⁺, and Ti⁴⁺ are isoelctronic ions. 1)Write the ground state noble gas configuration for each of these ions. 2)Which one of them would you expect to thave the smalles radius? 3)Rank then from smallest to largest.

Homework Equations

The Attempt at a Solution

1) I am not sure what to answer here, i know that in ionic form they all have the noble gas configuration of Ar, but what is the question asking for exactly? Is it asking for the configuration of these elements in neutral atom form?

2) Mn should have the smallest radius b/c it has the largest number of protons of the group and would pull the electrons in closer right?

3) In order they should be Mn, Ti, Sc, S, P, correct?

 

[Borek]

I guess they want just [Ar] for each one. And looks to me like you are right.

 

[k-rod AP 2010]

ok that's what i figured, but the wording was strange so i wanted to see if u guys could see something i didnt. thanks though