February 14th
Unit 4 Group Work – Molecule Structure
Please use this as a study tool. You do not need to turn it in. To be successful on the exam, you must have all
these concepts mastered. Problems that will discussed at the end of class are indicated with a box.
1. Complete the table:
Electron Configuration
Possible Anions
Possible Cations
Corresponding Noble
Gas
1s2
H-
Li+, Be2+, B3+
[He]
[Ar]
N3-, O2-, F-
2. Complete the table:
Na
Element
Electron Orbital
Diagram
[Ne]
Al
N
Se
.
Lewis Symbol for
the atom
Using the Energy
Diagram, explain
why the atom has
a common charge.
Losing one electron
from the 3s orbital
will result in a noble
gas configuration
Draw a Lewis
symbol for the ion
3. Show a Lewis Structure for the following ionic compounds:
LiBr
MgF2
4. Draw a complete Lewis Structure for each of the following molecules. Assign formal charge to all
atoms. Please make sure to complete the circled structures during class.
F2
O2
N2
CO
CO2
CO32-
NH4+
CN-
ClO-
CH3CH2NH2
ClO2-
5. NO3- is a common polyatomic ion. This problem will work through proving that Nitrogen must be the
central atom.
a. Draw a Lewis structure of NO3- with Nitrogen as the central atom. Assign formal charge to each
atom.
b. Draw two more resonance structures with Nitrogen as the central atom.
c. Draw a Lewis structure of NO3- with one of the oxygen atoms as the central atom. Assign
formal charge.
d. Comment on why nitrogen MUST be the central atom.
6. Draw a Lewis structure for the ionic compounds that form between:
a. Magnesium and nitrogen
b. Aluminum and oxygen
c. Sodium and phosphorus
d. CO32- and NH4+
.