Intro to Chemistry Chem 1020 Lab Molecular Models

Intro to Chemistry Chem 1020 Lab Molecular Models: Lewis Structure and VSEPR Theory Chemistry Department Minneapolis Community & Technical College 1

Overview • Part I Molecular modeling kit • Part II Data sheet 2

Part I. Molecular Modeling Kit Cover Content 3

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

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: 1. count the total number of valence electrons from all atoms present; 2. draw its Lewis structure; 3. make its 3 D model using the molecular modeling kit; 4. determine the total number of electron regions around the central atom; 5. describe its electronic geometry in words; 6. determine the number of bonding regions around the central atom; 7. determine the number of nonbonding regions around the central atom; 8. describe its molecular geometry in words; 9. sketch its 3 D structure. 5

Example: H 2 O Total valence e- Lewis structure 3 D Model 6 + 1× 2 = 8 e- # of bonding regions around central atom # of nonbonding regions around central atom Molecular geometry 2 2 V-shape (or bent) Total e- regions around central atom Electronic geometry 4 Tetrahedral Sketch 6

• 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 copy other students’ answers. • Turn in the data sheet the next time when you are expected to come to the lab. • Don’t forget to prepare for the next lab before you come next time. 7