types of radii

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Montana James 4G
Posts: 46
Joined: Wed Sep 18, 2019 12:21 am

types of radii

Postby Montana James 4G » Wed Oct 23, 2019 1:42 pm

I understand the tendency for radii to increase down a group and decrease across a period, but what's the difference between atomic, ionic, and covalent radii? thanks in advance :)

Emily Chirila 2E
Posts: 68
Joined: Sat Jul 20, 2019 12:16 am

Re: types of radii

Postby Emily Chirila 2E » Wed Oct 23, 2019 2:06 pm

Atomic radius refers to half the distance between centers of neighbors atoms. Covalent radius refers to specifically the radius between atoms that are joined by a covalent bond (2 nonmetals). Ionic radius is specifically for atoms joined by an ionic bond.

They all have the same trends, just covalent and ionic are more specific terms for the types of bonds in a given situation/problem

Posts: 51
Joined: Fri Aug 30, 2019 12:17 am

Re: types of radii

Postby LReedy_3I » Thu Oct 24, 2019 9:37 pm

atomic radii is calculate by half the distance between two nuclei, and the other two are the same concept except for elements in ionic and covalent bonds.While the trend for all of these is the same, it isn't systematic in the d-block. Also, atomic radii of cations are always smaller than their parent atoms, while radii of anions are always larger.

Alexa Mugol 3I
Posts: 54
Joined: Sat Aug 17, 2019 12:17 am

Re: types of radii

Postby Alexa Mugol 3I » Fri Oct 25, 2019 11:15 am

I think we should just know the general periodic trends of atomic radii. I asked my TA if we needed to know much about covalent radii (because Dr. Lavelle didn't really go into much detail), but I don't think we need to know it in detail, just the general trends.

Kaitlyn Jang 1F
Posts: 45
Joined: Sat Aug 17, 2019 12:16 am

Re: types of radii

Postby Kaitlyn Jang 1F » Sat Oct 26, 2019 5:36 pm

All of these types of radii share the same periodic trends, however atomic radii is just specifically referring to the half distance between two atoms while covalent radii is for 2 atoms covalently bonded, and ionic is for 2 atoms with an ionic bond.

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