question on another chem problem

[tlcmqn]

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Which of the following lists the atoms/ ions in decreasing order by size?

Answer : Te2- , I-, Xe, Cs+, Ba2+ , La3+

It doesn't make sense to me because I thought atomic radii increases from right to left and going down the column.
So then Cs+ would be the biggest of the above.

 

[Philippines03j]

Ok that is true but the charge also plays a role in size. A anion (+) decreases in size from the atom and an ion (-) increases in size. The following is in order from biggest to smalles Na-> Na > Na+

Hope that helps a little!

 

[Danny289]

Which of the following lists the atoms/ ions in decreasing order by size?

Answer : Te2- , I-, Xe, Cs+, Ba2+ , La3+

It doesn't make sense to me because I thought atomic radii increases from right to left and going down the column.
So then Cs+ would be the biggest of the above.

for solving this problem think this way, all of them have 54 electrons, that means same layers. Now ask yourself which one has more protons that one will be smaller.
answer:
La+3< Ba+2<Cs+1<Xe<I-<Te-2
hope it helped, good question 👍

 

[tdkyun]

Think of it like this.
More protons you have, more attraction you will have for electrons in the clouds. La3+ has the most protons, so those protons will pull electrons toward the nucleus the tightest. (hence smaller radius)

 

[Hot Homer]

The way I understood it was the electron cloud is what takes up the most space. If you have less electrons than that cloud/space will be smaller. So +3< +2<+1.

 

[klutzy1987]

The way I understood it was the electron cloud is what takes up the most space. If you have less electrons than that cloud/space will be smaller. So +3< +2<+1.

No it depends on how many protons the molecule has, the more protons something has the smaller it is because there is a stronger pull towards the middle making the radius smaller. Therefore if all ions have the same number of electrons and are in the same subshell level then the one that has the most protons will be the smallest. Therefore Na+ is smaller than Ne and F-.