how would the symmetry and polarity of a molecule be affected in the case of non-identical attached atoms 

Expert Answers
jerichorayel eNotes educator| Certified Educator


In order to answer this question, we try to compare two kinds of compounds.

For example: methane (CH4) and bromochloromethane (CH2BrCl)

.             H                                                                                             .             |                                                                                                     .      H -- C --H                                                                                                 .             |                                                                                                             .             H

There are FOUR C-H bonds.

The first compound, CH4 is symmetrical in all directions. All the H's exerts equal amount of electronegative force towards C therfore all the directions cancels out which makes the compound non-polar.


.             H                                                                                             .             |                                                                                                     .      H -- C --Cl                                                                                                 .             |                                                                                                             .             Br

There are TWO C-H bonds, ONE C-Br bond and ONE C-Cl bond.

For the second compound, imagine the two H's of CH4 is replaced by a Br and a Cl. CH2BrCl is not symmetrical. The presence of non-identical atoms in the compound makes it not symmetrical. It's polarity as well will change. Br and Cl exerts a force with C differently as what H can do to C. Since there are different atoms attached in the C it will now become polar.





Hope this helps :)