Arrange the following six atoms or ions in order of size, from smallest to largest.? #K, F^+, Rb, Co^(25+), Br, F, Rb ^- #

#K, F^+, Rb, Co^(25+), Br, F, Rb ^- #

1 Answer
anor277
Jun 9, 2018

I don't believe you got #Co^(25+)#...

Explanation:

Atomic size decreases ACROSS a Period, from left to right as we face the table, and INCREASES down a Group.

Why? Because atomic size is reasonably the radius of the valence, the outermost, electron. Should that valence electron be oxidized, the radius of the cation SHOULD be SUBSTANTIALLY smaller than that of the parent atom.

So we got ...#K (Z=19), F^+(Z=9),Rb(Z=37), Br(Z=35), F(Z=9), Rb^(-)(Z=37)#...

So in order of increasing ATOMIC/PARTICLE SIZE...

#underbrace(F^+, F,K, Br, Rb, Rb^-)_rarr#
#""^"increasing atomic/ionic size..."#

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