Cation and Anion Size

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sonalivij
Posts: 70
Joined: Fri Sep 28, 2018 12:27 am

Cation and Anion Size

Postby sonalivij » Fri Nov 02, 2018 5:22 pm

Why are cations smaller than their parent atoms if the loss of an electron would move them further to the left in a period. Wouldn't this make them larger? Also why are anions larger than their parent atoms if gaining an electron would move them further to the right in a period, which would make them smaller?

Nicholas Carpo 1L
Posts: 36
Joined: Fri Sep 28, 2018 12:19 am

Re: Cation and Anion Size

Postby Nicholas Carpo 1L » Fri Nov 02, 2018 5:55 pm

Cations are smaller because since they have less electrons than their parent atoms, they are pulled in more closely by the protons (which are unchanged) in the nucleus. The opposite goes for anions where they have increased electron repulsion.

Sean Reyes 1J
Posts: 67
Joined: Fri Sep 28, 2018 12:24 am

Re: Cation and Anion Size

Postby Sean Reyes 1J » Sat Nov 03, 2018 5:08 pm

The loss of electrons means that the protons will have a stronger pull on the core electrons, as the charge is now positive. This means the electron cloud will decrease in size.

Andrewwiner4D
Posts: 32
Joined: Fri Sep 28, 2018 12:28 am

Re: Cation and Anion Size

Postby Andrewwiner4D » Sun Nov 04, 2018 3:04 pm

The trend is based on the fact that the ratio of protons to electrons in the shell becomes greater. There are more protons than electrons, so the shell will not be able to expand as far with the greater pull.


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