# Problem: The ionic radii of the ions S2–, Cl–, and K+ are 184, 181, 138 pm respectively. Explain why these ions have different sizes even though they contain the same number of electrons.

###### FREE Expert Solution
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###### FREE Expert Solution

We’re being asked to explain why the ionic radius of the following ions have different sizes even though they contain the same number of electrons.

Recall that ionic radius is the size of an ion. The trend for ionic radius is as follows: it increases from right to left and down a period in the periodic table. Ionic radius also increases with increasing number of electrons.

For this problem, we need to do the following:

Step 1: Determine the electrons in each species.

Step 2: Compare the charges if they are isoelectronic.

97% (357 ratings)
###### Problem Details

The ionic radii of the ions S2–, Cl, and K+ are 184, 181, 138 pm respectively. Explain why these ions have different sizes even though they contain the same number of electrons.

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Periodic Trend: Ionic Radius concept. You can view video lessons to learn Periodic Trend: Ionic Radius Or if you need more Periodic Trend: Ionic Radius practice, you can also practice Periodic Trend: Ionic Radius practice problems .

How long does this problem take to solve?

Our expert Chemistry tutor, Shreya took 2 minutes to solve this problem. You can follow their steps in the video explanation above.

What professor is this problem relevant for?

Based on our data, we think this problem is relevant for Professor Walker's class at TEXAS.

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