Arranging Cl, S2−, K, K+, O by increasing radius

[bebelova]

1. a) Arrange the following atoms or ions in order of increasing radius:
Cl, S2-, K, K+, O
b) Give an explanation for the position of S2- in relation to the atom or ion that comes just before and just after it.

I was not sure that is why i am posting these..

my answer is...
1. a) K>K+>S2->Cl>O (im still not sure because K+and S2- has same number)

b) [I DIDNT GET THIS SENTENCE..-_- BUT I WAS TRING TO ANSWER AS..]

S2- is in middle position of these atoms and ions because this gains 2- atomic number(?!)

Pleas hellllpppp~

 

[GCT]

You need to find the term effective nuclear charge through the index of your text, I believe that this will be in direct correlation with your answer (Zeff=proton number - electron shielding). Also, try finding images of cations and anions in your text, search through the atomic structure chapter (body centered, closed packed, etc...).

In general, if you have two atoms with the same atomic number, a cation<neutral<anion in radii.

For the second question, you'll need to consider the relative positions in relevance to the quantum level (I forgot the appropriate term), i.e. 1s2,2s2,2p6,3s2.