Chemistry Questions Molecular Polarity (Page 2 of 4) in pdf

Chemistry Questions Molecular Polarity Page 2

Lone pair electrons double bonds, and triple bonds are also areas of molecules that are slightly negative

because of the increased charge density.

Charge density triple bond > charge density double bond> charge density of single bond

Why does increasing the number of pi bonds add to charge density?

The distribution of negative and positive charges in the molecule determines is the molecule itself is polar. The

greater the difference between the center of positive charges and the center of negative charges the more polar

the molecule is. The distance from the center of positive charges to the center of negative charges is a vector

quantity called dipole moment.

Build models and draw sketches of CH

, CH

Cl, CH

, CHCl

, and CCl

Is the carbon-hydrogen bond polar?

Is the carbon-chlorine bond polar? Which atom is negative and which is positive?

The center of negative charge is in the middle of the chlorines and the center of positive charges is the carbon.

Which of the CH

Cl, CH

, CHCl

, and CCl

molecules has the biggest distance between the center of

positive and negative charges?

Why is the center of negative and positive charges the same in CCl

Draw a sketch of BBr

Is the boron-bromine bond polar or nonpolar?

Locate the center of positive and negative charge in the BBr

molecule. Why is the molecule nonpolar?

In general molecular polarity can be summed up as follows:

Negative areas of a molecule are caused by more the electronegative atom of polar bonds, with the strength of

the negative charge increasing with higher percentage ionic character. Lone pairs and pi bonds produce weaker

areas of negative charge.

If a molecule has no polar bonds, lone pairs, or pi bonds it cannot be polar.

If a molecule has negative charges distributes symmetrically it is not polar.

If polar bonds are on the opposite end of a molecule from nonpolar bonds the molecules will be polar because

the centers of positive and negative charge will be far apart.

Chemistry Questions Molecular Polarity Page 2