Understanding Ionic Radius

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Rohan Kubba Dis 4B
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Joined: Sat Aug 17, 2019 12:18 am

Understanding Ionic Radius

Postby Rohan Kubba Dis 4B » Sat Nov 02, 2019 11:02 am

In the review session, the UAs mentioned three ions that were isoelectronic, meaning they were equal in valence electrons, however, in this case they explained that ionic radius still increases as you move down a group and increases as you go down a period. I’m just confused as to why this is the case if all of the elements have the same amount of electrons in their shells. Does it have to do with the amount of protons in an element?

Posts: 107
Joined: Sat Aug 24, 2019 12:17 am

Re: Understanding Ionic Radius

Postby Goyama_2A » Sat Nov 02, 2019 11:17 am

Yes, as elements move to the right in a period, they have more protons, resulting in a high effective nuclear charge (in other words, a stronger pull) on each electron from the nucleus. This stronger pull leads to a smaller radius.

Jasmine Summers 4G
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Joined: Wed Sep 18, 2019 12:17 am

Re: Understanding Ionic Radius

Postby Jasmine Summers 4G » Sat Nov 02, 2019 11:46 am

ionic radius decreases toward the right since the electrons are pulled in loser, but then increase down since the energy level of the elements increases that direction

Catherine Daye 1L
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Joined: Wed Sep 11, 2019 12:16 am

Re: Understanding Ionic Radius

Postby Catherine Daye 1L » Sat Nov 02, 2019 12:39 pm

Yes, because even though isoelectronic ions have the same number of electrons, they still have differing numbers of protons. When there are more protons in the nucleus, there is a stronger pull. Therefore, isoelectronic ions have the same electron-electron repulsion but different pulls from the nucleus.

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