In increasing order, how would you rank these ions according to ionic radius? #Sr^+2#, #Br^-#, #Rb^+#, #As^-3#, #Se^-2#

1 Answer
Aug 9, 2016

Can you not get your Periodic Table, and classify the ions according to size?


It is well known that for #"NEUTRAL atoms"#, size DECREASES across a Period from left to right as we face the Table, and INCREASES down a Group.

For parent atoms in the same Period, ANIONS are going to be intrinsically larger, because electrons are added to the valence shell, the which expands. Cations of the same Period are going to be intrinsically smaller, because a valence shell may be entirely removed. Have a stab at it, and report the results back here.