Editing Polarizability (section)

==Atomic and molecular polarizability==
Generally, polarizability increases as the volume occupied by electrons increases.<ref name="anslyn"/> In atoms, this occurs because larger atoms have more loosely held electrons in contrast to smaller atoms with tightly bound electrons.<ref name="anslyn"/><ref name="Schwerdtfeger">{{cite book |last1=Schwerdtfeger |first1=Peter |title=Atomic Static Dipole Polarizabilities |publisher=[[IOS Press]] |year=2006 |editor=G. Maroulis |chapter=Computational Aspects of Electric Polarizability Calculations: Atoms, Molecules and Clusters}}[http://www.worldscibooks.com/etextbook/p464/p464_chap01.pdf]{{dead link|date=January 2018|bot=InternetArchiveBot|fix-attempted=yes}}</ref> On rows of the [[periodic table]], polarizability therefore decreases from left to right.<ref name="anslyn"/> Polarizability increases down on columns of the periodic table.<ref name="anslyn"/> Likewise, larger molecules are generally more polarizable than smaller ones.

Water is a very [[chemical polarity|polar]] molecule, but [[alkanes]] and other [[hydrophobic]] molecules are more polarizable. Water with its permanent dipole is less likely to change shape due to an external electric field. Alkanes are the most polarizable molecules.<ref name="anslyn"/> Although [[alkenes]] and [[arenes]] are expected to have larger polarizability than alkanes because of their higher reactivity compared to alkanes, alkanes are in fact more polarizable.<ref name="anslyn"/> This results because of alkene's and arene's more electronegative sp<sup>2</sup> carbons to the alkane's less electronegative sp<sup>3</sup> carbons.<ref name="anslyn"/>

Ground state electron configuration models often describe molecular or bond polarization during [[chemical reaction]]s poorly, because [[reactive intermediate]]s may be excited, or be the minor, alternate structures in a [[chemical equilibrium]] with the initial reactant.<ref name="anslyn">{{cite book |last1=Anslyn |first1=Eric |title=Modern Physical Organic Chemistry |last2=Dougherty |first2=Dennis |author-link2=Dennis A. Dougherty |publisher=University Science |year=2006 |isbn=978-1-891389-31-3}}[https://books.google.com/books?id=gY-Sxijk_tMC&dq=organic+chemistry+polarizability&pg=PA25]</ref>