Shape and polarity play a large part in the characteristics of any given substance. give an example of how these influence a molecule’s behavior.

Explanation:

Shape and polarity determine which type of compounds is.

if the shape of molecule is symmetric it will non polar. And it will dissolve in non polar solvent. The polar molecules are trigonal in shape.

Sodium chloride is ionic compound. The electronegativity of chlorine is 3.16 and for sodium is 0.93. There is large difference is present. That's why electron from sodium is transfer to the chlorine. Sodium becomes positive and chlorine becomes negative ion and compound is polar.

The compound having ionic bonds generally have moderate to high boiling points and melting point because of greater electrostatic interaction. Their electrical conductivity are high and these minerals tend to dissolve in water.

Covalent bond:

It is formed by the sharing of electron pair between bonded atoms.  

The atom with larger electronegativity attract the electron pair more towards it self and becomes partial negative while the other atom becomes partial positive and compound will polar.

For example:

In water the electronegativity of oxygen is 3.44 and hydrogen is 2.2. That's why electron pair attracted more towards oxygen, thus oxygen becomes partial negative and hydrogen becomes partial positive.

If the ectronegativity difference is 0.4 or less than this the compound will be non polar covalent compound and will behave different from polar compound.