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Polarizability vs Polarizing Power Trends

Posted: Sun Nov 18, 2018 12:14 am
by Nathan Tran 4K
What is this trend on the periodic table for polarizability and polarizing power and how do you justify these trends using ideas like more shells and greater effective nuclear charge?

Re: Polarizability vs Polarizing Power Trends

Posted: Sun Nov 18, 2018 8:38 am
by Jane Burgan 1C
Since polarizability is when atoms and ions have electron clouds that easily undergo large distortion, larger atoms are more polarizable compared to smaller atoms. So, polarizability increases going down a group, but decreases going across a period. When you go down a group, there are more shells being added to the atom, so the electrons are farther away from the nucleus - the nucleus isn't able to exert as strong as a force to pull the electrons together and there's also a shielding effect from other electrons. Thus, the size of the atom is larger due to these factors, so its polarizability increases.

Polarizing power is when atoms and ions can cause large distortions in the electron clouds of other atoms. An atom has greater polarizing power when it has a smaller radius and is highly charged because then its nucleus can get close to the other atom and pull on its electrons. Polarizing power decreases going down a group, and increases going across a period, so it's the opposite of polarizability.