## Atomic Radius

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Sunia Akaveka 4I
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### Atomic Radius

This could be such a basic question but how do you find atomic radius? To be honest, I looked at the solutions manual (specifically for 1F.1 where it asks to list the elements in order of decreasing atomic radius) and still don't understand how the measurement is obtained. Anything helps, thanks!

Tai Metzger 3K
Posts: 103
Joined: Sat Aug 24, 2019 12:17 am

### Re: Atomic Radius

In general, the periodic table has the following trends for atomic radius:
As you move down a column, atomic radius increases.
As you move from left to right along a row, the atomic radius decreases.

Sunia Akaveka 4I
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Joined: Sat Sep 14, 2019 12:17 am
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### Re: Atomic Radius

Tai Metzger 3K wrote:In general, the periodic table has the following trends for atomic radius:
As you move down a column, atomic radius increases.
As you move from left to right along a row, the atomic radius decreases.

Wait, actually that sounds very familiar and I think I knew that subconsciously. Hahah thanks! But by any chance, do you know how to obtain the specific number?

Cynthia Gong 1L
Posts: 51
Joined: Fri Aug 09, 2019 12:15 am

### Re: Atomic Radius

The atomic radius is half the distance between the nuclei of two identical atoms bonded together. For the purpose of this class I don't think we would be calculating the exact value of the radius.

Emma Popescu 1L
Posts: 105
Joined: Wed Sep 11, 2019 12:16 am

### Re: Atomic Radius

We won't need to calculate the value of atomic radius. If needed, the values should be given to us.

Ayushi2011
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Joined: Wed Feb 27, 2019 12:17 am

### Re: Atomic Radius

The value of atomic radius will always be given to us.

Julieta Serobyan4D
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Joined: Wed Sep 11, 2019 12:17 am

### Re: Atomic Radius

Atomic radius is usually given in a data booklet or just in the front page of the test.

Mariah
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Joined: Fri Aug 02, 2019 12:16 am

### Re: Atomic Radius

Cynthia Gong 1L wrote:The atomic radius is half the distance between the nuclei of two identical atoms bonded together. For the purpose of this class I don't think we would be calculating the exact value of the radius.

During the lecture, a picture was shown that said 2r from both nuclei of atoms bonded together. Do you know what that meant? It confused me because he said it's half the distance but then it said 2r.

Verity Lai 2K
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Joined: Sat Aug 24, 2019 12:18 am

### Re: Atomic Radius

I think we will always be given the atomic radius and I think the 2r was to help us understand how the atomic radii was calculated.

Robert Tran 1B
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Joined: Thu Jul 11, 2019 12:15 am

### Re: Atomic Radius

The atomic radius is usually determined experimentally by halving the distance between the nuclei of two atoms. There isn't a formula that I know of that can allow us to solve for the atomic radius of a given element/ion.

PriscillaLi_3G
Posts: 63
Joined: Fri Sep 27, 2019 12:30 am

### Re: Atomic Radius

A visual of the atomic radius trend in the periodic table:

https://www.google.com/url?sa=i&rct=j&q ... 1235927497

KBELTRAMI_1E
Posts: 108
Joined: Sat Jul 20, 2019 12:17 am

### Re: Atomic Radius

Tai Metzger 3K wrote:In general, the periodic table has the following trends for atomic radius:
As you move down a column, atomic radius increases.
As you move from left to right along a row, the atomic radius decreases.

Do we need to know the exact number though?

Michelle Le 1J
Posts: 50
Joined: Fri Aug 09, 2019 12:16 am

### Re: Atomic Radius

No I don't think you need to know exactly how much the atomic radius changes, I would just know and understand the trends as you go down a group and across a period

Brittany Tran 3I
Posts: 50
Joined: Sat Jul 20, 2019 12:16 am

### Re: Atomic Radius

I don't think we need to calculate atomic radius directly, but it's defined as half the distance between the centers of two neighboring atoms

Anvi Brahmbhatt 4A
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Joined: Wed Sep 18, 2019 12:21 am

### Re: Atomic Radius

We probably do not need to calculate the atomic radius, but understand the periodic trend explained in the posts above!

McKenna_4A
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Joined: Sat Aug 24, 2019 12:18 am

### Re: Atomic Radius

You won't ever be asked to calculate the actual value of atomic radii. Just know the trends.

Cassandra_1K
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Joined: Wed Sep 18, 2019 12:16 am

### Re: Atomic Radius

How do you differentiate between Atomic and Ionic Radius because I know they both increase when going down a group and decrease from left to right, so how are they different?

Megan Jung 3A
Posts: 50
Joined: Thu Jul 11, 2019 12:17 am

### Re: Atomic Radius

In terms of looking at trends on the periodic table of atomic radii, the atomic radius can be defined as half the distance between to bonded atoms. This is because since electrons don't have a specific location, you cannot calculate exactly the distance between the center of the atom and the end of it.

Nathan Nakaguchi 1G
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### Re: Atomic Radius

The atomic radius is half the distance between the centers of neighboring atoms, I don't think we will have to ever calculate a measurement for this (it would probably be given). I believe to answer this question you go based off of the periodic trends of atomic radii, as you go down and left of the periodic table radius increases. So you compare the relative locations of the atoms of the periodic table based off of how far down and how far left they are ie the size of their radii.

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