Molecular Form, Shape, Bond Angles And Polarity Worksheet printable pdf download

Molecular Form, Shape, Bond Angles And Polarity Worksheet

Determining the molecular shape, bond angles and polarity from a Lewis dot structure

A. Draw a correct Lewis dot structure of the molecule or ion

1. Count the total number of valence electrons in the molecule or ion. Any charge on an ion will either add (if a

negative ion) or subtract (if a positive ion) the number on the charge to/from the total number of valence electrons.

2. Arrange the atoms in the molecule or ion in such a way that the basic connectivity is shown. For most simple

Lewis dot structures, there is a single central atom flanked by the other atoms.

3. Start by drawing single bonds between the central atom and all the other atoms. Recall that a single bond counts

as two electrons.

4. Continue by adding lone pairs as necessary to fulfill the octet rule on those atoms that follow the octet rule (for

instance, hydrogen follows the duet rule, so by drawing a single bond to a hydrogen, you have already fulfilled the

duet rule for that hydrogen).

5. Count the total number of valence electrons in the structure you’ve drawn. If this number matches the number in

step 1, then you are done. If this number is greater than the number in step 1, replace a single bond with a double

bond, and remove a lone pair from each of the atoms connected by the new double bond. Continue this

replacement of single bonds by double bonds until the number of valence electrons in the structure matches the

number of valence electrons found in step 1.

6. If the structure is that of an ion, put large brackets around the ion’s structure, then add the charge of the ion as a

superscript.

B. Determining the molecular shape and bond angles.

1. Identify the central atom in the Lewis dot structure.

Molecular Form, Shape, Bond Angles And Polarity Worksheet