Molecular Models: Lewis Structure and VSEPR Theory

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Molecular ModelsLewis Structure and VSEPR Theory
Intro to Chemistry Chem1020 Lab

• Chemistry Department
• Minneapolis Community Technical College

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Overview

• Part I
• Molecular modeling kit
• Part II
• Data sheet

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Part I. Molecular Modeling Kit
Cover
Content
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Atoms
4 holes C, N, O, or F
1 hole Hydrogen
4 holes C, N, O, or F
4 holes C, N, O, or F
(Note The underlined element(s) is/are the
preferred one(s) representing that specific
color.)
Attachments
One of the multiple bonds (long and flexible)
One nonbonding (or lone) pair
Single bond (short and rigid)
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Part II. Data Sheet

• You will obtain a data sheet at the beginning of
  the lab. The sheet includes 10 species that
  contain covalent bonds. For each species, you
  need to
• count the total number of valence electrons from
  all atoms present
• draw its Lewis structure
• make its 3D model using the molecular modeling
  kit
• determine the total number of electron regions
  around the central atom
• describe its electronic geometry in words
• determine the number of bonding regions around
  the central atom
• determine the number of nonbonding regions around
  the central atom
• describe its molecular geometry in words
• sketch its 3D structure.

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Example H2O
Total valence e- Lewis structure 3D Model Total e- regions around central atom Electronic geometry
6 12 8 e- 4 Tetrahedral
of bonding regions around central atom of nonbonding regions around central atom Molecular geometry Sketch
2 2 V-shape (or bent)
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• Dissemble all of molecule models and put pieces
  back to the kit container according to the
  picture on page 3.
• Ask your instructor to sign you out.then you are
  ready to leave.
• Finish the data sheet after the lab. Feel free
  to ask instructors questions, but never ever copy
  other students answers.
• Turn in the data sheet the next time when you are
  expected to come to the lab.
• Dont forget to prepare for the next lab before
  you come next time.