Atomic Radius

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Jaci Glassick 2G
Posts: 104
Joined: Sat Jul 20, 2019 12:16 am

Atomic Radius

Postby Jaci Glassick 2G » Tue Oct 15, 2019 8:30 am

In homework question 1F1, we are asked to to arrange elements in decreasing order of atom radius. I know there is a way to find radius using the periodic table (atomic radius increases as you go down the table and decreases as you go right). Is there a better way to find atomic radius?

Sharon Rodriguez 3H
Posts: 50
Joined: Wed Nov 14, 2018 12:18 am

Re: Atomic Radius

Postby Sharon Rodriguez 3H » Tue Oct 15, 2019 3:21 pm

I believe this is the simplest way to find the atomic radius without having to do any calculations.

Sartaj Bal 1J
Posts: 101
Joined: Thu Jul 25, 2019 12:17 am

Re: Atomic Radius

Postby Sartaj Bal 1J » Thu Oct 17, 2019 12:42 am

To add on, atomic radius increases down a group with each new period because the outermost electrons occupy shells with increasing principal quantum number and therefore lie farther from the nucleus. Atomic radius decreases across a period because new electrons are in the same shell of the atom and about as close to the nucleus as other electrons in the same shell. Because of this configuration, electrons do not shield one another well from the nuclear charge so the effective nuclear charge increases across the period. This draws the electron in so the atom is more compact as a result.

Caroline Zepecki
Posts: 101
Joined: Fri Aug 09, 2019 12:16 am

Re: Atomic Radius

Postby Caroline Zepecki » Thu Oct 17, 2019 9:23 am

Are there specific values somewhere on the periodic table that can be used to determine atomic radius or do you just have to determine comparatively by location?

Jocelyn Thorp 1A
Posts: 103
Joined: Wed Sep 18, 2019 12:20 am

Re: Atomic Radius

Postby Jocelyn Thorp 1A » Thu Oct 17, 2019 9:57 pm

Sartaj Bal 3H wrote:To add on, atomic radius increases down a group with each new period because the outermost electrons occupy shells with increasing principal quantum number and therefore lie farther from the nucleus. Atomic radius decreases across a period because new electrons are in the same shell of the atom and about as close to the nucleus as other electrons in the same shell. Because of this configuration, electrons do not shield one another well from the nuclear charge so the effective nuclear charge increases across the period. This draws the electron in so the atom is more compact as a result.


thank you... I've been wracking my brain trying to figure out why it decreases across the row


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