ionic radii

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Jared_Yuge
Posts: 100
Joined: Sat Aug 17, 2019 12:17 am

ionic radii

Postby Jared_Yuge » Tue Nov 05, 2019 10:57 pm

why is it that an anion has a larger radius than its parent atom, I thought that when we add electrons the attraction gets stronger with the nucleus and it gets pulled in making it smaller.

Justin Vayakone 1C
Posts: 110
Joined: Sat Sep 07, 2019 12:19 am

Re: ionic radii

Postby Justin Vayakone 1C » Tue Nov 05, 2019 11:16 pm

Actually, when we add electrons, the attractive pull between the nucleus and electrons are weaker. With more electrons to pull in, the force is weaker. There is also added repulsion between the electrons that cause them to be further apart, creating a larger radius.

Charysa Santos 4G
Posts: 107
Joined: Wed Sep 18, 2019 12:21 am

Re: ionic radii

Postby Charysa Santos 4G » Thu Nov 07, 2019 11:44 am

An anion has a larger radius than its neutral atom because when you add an electron, the repulsive forces between the electrons is relatively greater than the pull of the positively-charged nucleus, thus causing the electrons to further apart, making the anion's radius larger.

Jasmine Fendi 1D
Posts: 108
Joined: Sat Aug 24, 2019 12:15 am

Re: ionic radii

Postby Jasmine Fendi 1D » Thu Nov 07, 2019 11:52 am

In addition to the comments above, the atomic radii decreases as you move towards the right of a period. This is because as you move right, the added electrons are added to the same n level but the number of protons in the nucleus increases. The protons have a much greater effect than the added electrons, so the protons actually have more pull on the electrons towards the nucleus.

Claire Grover 3G
Posts: 64
Joined: Wed Sep 18, 2019 12:18 am

Re: ionic radii

Postby Claire Grover 3G » Thu Nov 07, 2019 12:40 pm

As the people above said, cations are larger than the neutral atoms because there are more electrons that are pushing against each other and expanding the radios. The atomic radius of neutral elements decreases across a period because there are also increasing amounts of protons pulling in the electrons more and more. With a cation, an electron is added but no proton, so it doesn't become smaller.


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