Comparing Cations and Parent Atom Atomic Radius

Moderators: Chem_Mod, Chem_Admin

Srbui Azarapetian 2C
Posts: 54
Joined: Thu Jul 13, 2017 3:00 am
Been upvoted: 2 times

Comparing Cations and Parent Atom Atomic Radius

Postby Srbui Azarapetian 2C » Sun Nov 05, 2017 4:12 pm

I know that atomic radii decreases from left to right across a period as the effective atomic number increases, and they increase down a group as successive shells are occupied. Also that cations are smaller than their parent atoms and anions larger. However, when comparing for example, Cs+1 and Ba, Cesium would originally be larger, but since it is in its cation form, does it decrease in size so much that it is smaller than the Barium?

Jason Liu 1C
Posts: 52
Joined: Fri Sep 29, 2017 7:04 am

Re: Comparing Cations and Parent Atom Atomic Radius

Postby Jason Liu 1C » Sun Nov 05, 2017 4:25 pm

Yes. If you refer to figure 2.20, on page 51 you can see that the atomic radius of Ba is 217 pm. In figure 2.22 on page 52, it shows that Cs+1 has an atomic radius of 167 pm.

Angel R Morales Dis1G
Posts: 50
Joined: Sat Jul 22, 2017 3:01 am

Re: Comparing Cations and Parent Atom Atomic Radius

Postby Angel R Morales Dis1G » Mon Nov 06, 2017 3:01 pm

Srbui_Azarapetian3B wrote:I know that atomic radii decreases from left to right across a period as the effective atomic number increases, and they increase down a group as successive shells are occupied. Also that cations are smaller than their parent atoms and anions larger. However, when comparing for example, Cs+1 and Ba, Cesium would originally be larger, but since it is in its cation form, does it decrease in size so much that it is smaller than the Barium?

Cs +1 and Ba have the same number of electrons, but Cs has more protons. Therefore, the proton-electron attraction is much greater than in Ba, making it smaller.


Return to “Trends in The Periodic Table”

Who is online

Users browsing this forum: No registered users and 1 guest