Moderators: Chem_Mod, Chem_Admin

curry 1E
Posts: 55
Joined: Wed Sep 18, 2019 12:15 am


Postby curry 1E » Tue Nov 12, 2019 11:48 am

I am still confused with polarizing power, can someone help me put these in increasing power Rb+, Be2+, Sr2+

Posts: 105
Joined: Wed Sep 11, 2019 12:16 am
Been upvoted: 1 time

Re: 2D.9

Postby asannajust_1J » Tue Nov 12, 2019 11:54 am

Polarizing power depends on size and charge.
The smaller and higher the charge, the greater the ability to attract the electron cloud of the partial negative atom. Smaller atoms allow for less distance between atoms, so electrons can be easily distorted in a molecule, and a higher charge will allow it to have a stronger pull ability to distort the other electrons. Thus the order from decreasing to increasing is Rb+, Sr2+, Be2+.

Posts: 95
Joined: Wed Sep 11, 2019 12:17 am

Re: 2D.9

Postby BNgo_2L » Wed Nov 13, 2019 7:31 pm

Smaller cations have higher polarizing due to the minimal amount of electrons between the nucleus and the outer shell. When there is less electrons, the positive charge of the nucleus is able to distort the electron cloud of anions more easily.

Posts: 54
Joined: Thu Jul 25, 2019 12:15 am

Re: 2D.9

Postby NRodgers_1C » Sun Nov 17, 2019 9:43 pm

I used the trends of the periodic table to compare the polarizing power. First, I recognized that Be2+ was the most electronegative and as the most highly charged, had the greatest polarizing power. Then to compare Rb+ and Sr2+, I again compared electronegativity and atomic radius. Rb+ is less electronegative than Sr2+ and also has a bigger atomic radius. Therefore, I concluded that Sr2+ is both smaller and more highly charged than Rb+, indicating higher polarizing power. So I got Rb+< Sr2+<Be2+. Is this an acceptable way to go about the problem?

Jiapeng Han 1C
Posts: 91
Joined: Wed Sep 30, 2020 9:50 pm

Re: 2D.9

Postby Jiapeng Han 1C » Sat Nov 07, 2020 1:30 am

Cation with greater charge density--greater charge/size ratio--has greater polarizing power. So polarizing power: Rb+<Sr2+<Be2+.

Manseej Khatri 2B
Posts: 76
Joined: Wed Sep 30, 2020 9:42 pm

Re: 2D.9

Postby Manseej Khatri 2B » Sun Nov 08, 2020 11:44 pm

Hi, in the lecture, Dr. Lavelle said that polarizing power is to do with charge density, which is charge per volume. Larger elements have a larger volume and thus a smaller charge density. More charge also means a larger charge density. Be2+ should have the largest polarizing power, with a larger charge and smaller volume. Next would be Sr2+, same charge as Be2+ but larger volume. Finally Rb+, with a smaller charge, and larger volume compared to the other two. Increasing order would be: Rb+, Sr2+, Be2+.

Posts: 49
Joined: Wed Sep 30, 2020 9:39 pm

Re: 2D.9

Postby Yijia_Yang_3A » Wed Nov 11, 2020 7:12 am

The smaller the cation and the higher the charge, the greater the ability to distort the electron cloud. So, you want to compare these three elements in terms of size (electronegativity) and charge. We know Be2+ and Sr2+ have the same charge, so we find instead that Be is smaller than Sr, thus Be 2+ has higher polarizing power. So the list goes, from low to high, Rb+, Sr2+, Be2+

Return to “Polarisability of Anions, The Polarizing Power of Cations”

Who is online

Users browsing this forum: No registered users and 1 guest