Will write in own words

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Will write in own words. Pre-Lab Questions (Please use full sentences to answer these questions).

1.     When drawing a Lewis structure, what basic rule tells you where the electrons will be?

 

2.     What characteristics of a Lewis structure tell you whether a bond between two atoms is a single bond, a double bond, or a triple bond?

 

3.     What is the difference between a two-dimensional image and a three-dimensional image?

Background:

 

SHAPES OF MOLECULES

LINEAR

BENT

PYRAMIDAL

TETRAHEDRAL

 

 

 

 

 

lone pairs - are unbonded pairs of electrons.  These electrons must be drawn because they influence the shape of the molecule

bonded pairs - represent two electrons that are covalently bonded together.

 

 

 

 

 

Question

What can you predict about the structures of molecules by building models?

 

Procedure

1.     Print off a periodic table of electronegativities.

2.     Create a data table like the one below.

Table 1 2D Model Building (known also as Lewis Structures) - use Model in the simulation. 

Name

Formula

?EN

(show a complete calculation of each different bond in the molecule)

Bond Type

(non-polar covalent, slightly polar covalent, polar covalent)

Lewis Structure

(with bond polarity), drawn by hand

 

δ^-

δ^-

/Molecular Geometry and screenshot of the model 

Molecular Polarity

(polar or non-polar)

 

 

 

 

 

 

 

 

1.     Go to the website https://phet.colorado.edu/en/simulation/molecule-shapes .  Download the free simulation software.  Based on your Lewis structures, build the model of the first molecule in your table.

2.     In your table, write the name and formula, and draw a Lewis structure for each molecule below. (Please choose Model in the simulation) 

 

 

a.     Carbon bonded to 4 hydrogen atoms

b.     hydrogen bonded to chlorine

c.      oxygen bonded to two hydrogen atoms

d.     carbon bonded to two oxygen atoms

e.     nitrogen bonded to three hydrogen atoms

f.      carbon bonded to four chlorine atoms

g.     nitrogen bonded to three fluorine atoms

 

3.     Indicate the molecular geometry by ticking off Molecular Geometry and copy and paste a screenshot you have created based on the Lewis Structure you have drawn.  Don't forget to add lone pairs and the choice of type of bonding, where applicable. 

 

 

4.     Determine the molecular polarity.   Use section 3.3 of your text, page 106 or use the related lessons in the unitor the tutorial over here. 

5.     Switch now to Real Model and complete the below table with screenshots attached to the last column in the table  

Table 2 3D Models

Name

Formula

 

 

Real Model 

Water 

 

H₂O

 

Carbon Dioxide 

CO₂

 

Ammonia 

NH₃

 

Methane 

CH₄

 

6.     Choose ONE molecule from the table and explain using appropriate terms, the type of bonding and the molecular geometry. Terms like electronegativity, lone pairs, single/double/triple covalent bonds, dipoles, molecular polarity, need to be in your explanation. 

 

 

 

 

 

 

 

Analyze and Interpret

1.  Compare your Lewis Structures sketches and the Real models.  Discuss any differences.

 

Conclude and Communicate

2. What can you learn from models that you cannot learn from Lewis structures?

3. Summarize the strengths and Limitations of creating molecular models online.  What can you infer from the models?  What features cannot be inferred from the models?

 

Inquiry

4.     Describe the difference between ball and stick models and space-filling models. Do some research and discuss the advantages and disadvantages of using each types of model.

 

 

Research

5.     Using print and Internet resources, research a discovery of a structure in chemistry or biochemistry that depended heavily on model building.  Post an image of the model, along with a brief description of what the structure is, does, and where it's found on the forum - Structures in Chemistry and Biochemistry.