Smallest Atomic Radius: Cl-, K+, or Ar?

[mrjoe2]

Homework Statement

which has the smallest atomic radius: cl-, k+, Ar

Homework Equations

none

The Attempt at a Solution

i thought it was argon, but I am not sure because it does have the most protons to bringin the electrons. please someone reply soon!

 

[Gannon]

The radius of an atom is determined by its overall size and its electronegativity, but in this case the atoms are very similar in size. Chlorine is more electronegative and will pull its electrons in more, decreasing its radius. Potassium is very weakly electronegative, and would rather extend its electrons outward, increasing its radius. Argon is noble, and just sits in between.

 

[mrjoe2]

are you sure about this answer? i don't doubt you or anything, I am just making sure before i engrave this logic into my brain.

 

[mrjoe2]

i think its argon or potassium because they have the more protons and thus greater attractions. cl- is out for sure. it can't be right sorry

 

[Borek]

Note all three have the same number of electrons - they differ only by the nucleus charge. The higher the nucles charge, the stronger the attraction.

 

[opuktun]

Yes, I second to Borek answer.

The logic is simple. Positive (nucleus) attract negative (electrons).

So which is more in each atom? Positively charged species? Negatively charged species?

 

[Gannon]

Note all three have the same number of electrons - they differ only by the nucleus charge. The higher the nucles charge, the stronger the attraction.

Ah, I didn't even notice that the charges were the same!

 

[Borek]

Charges are not the same, number of electrons is.

 

[Gannon]

Of course; my mind has been a bit flighty the past few weeks. I guess I'll stop trying to help!

 

[Borek]

Of course; my mind has been a bit flighty the past few weeks. I guess I'll stop trying to help!

No need for that, just slow down when replying I am hitting the same wall now and again.