VESPR Theory and Molecular Shapes Lab

Make sense of problem and persevere in solving them Objective Today I will be able to: Draw Lewis Structures to represent the valance electrons of atoms Represent the formation of ionic and covalent compounds using Lewis Structures Predict the molecular shape of a molecule using the VSEPR theory Evaluation/ Assessment Informal assessment – Listening to group interactions as they complete the illustrating ionic and covalent compounds practice and the molecular shapes lab. Formal Assessment – Analyzing student responses to the exit ticket and the practice worksheets. Common Core Connection Make sense of problem and persevere in solving them Reason abstractly and quantitatively Use appropriate tools strategically Look for and make use of structure

Lesson Sequence Warm – Up Explain: VSEPR Theory Explore and elaborate: Molecular Shapes Lab Informal Assessment Evaluate: Exit Ticket Formal assessment

Warm - Up How do I determine the number of valence electrons an atom has? What does VSEPR stand for? Draw the lewis structure for N2

Warm-Up (Day 2) What bond angles does a tetrahedral shaped molecule have? Draw the lewis structure for N2 What shape and angle does this structure have?

Objective Today I will be able to: Draw Lewis Structures to represent the valance electrons of atoms Represent the formation of ionic and covalent compounds using Lewis Structures Predict the molecular shape of a molecule using the VSEPR theory

Homework Have a great weekend 

Agenda Warm-Up VESPER Notes Molecular Shapes Lab Exit Ticket

Drawing Lewis Structures

Lewis Structures Visual representation of the number of valance electrons in an atom

How to draw Lewis structures Write the symbol of the element Pretend there are 4 sides Use dots to represent the valance electrons around the symbol Place one dot on each side of the element before you form pairs Exception: If there are only 2 valance electrons, they both go on the same side

Lewis Structures C 1s2 2s2 2p2 • • • C •

Lewis Structures Examples Mg 1s2 2s2 2p6 3s2 • Mg •

Lewis Structures Cl 1s2 2s2 2p6 3s2 3p5 • • • • Cl • • •

[ ] • • • • • • • • Cl Lewis Structures -1 Cl 1s2 2s2 2p6 3s2 3p5

VSEPR Theory Notes

Valance – Shell Electron Pair Repulsion Theory (VSEPR) In a small molecule, the pairs of valance electrons are arranged as far apart from each other as possible Explains why atoms form certain shapes when they bond together

Linear Bonds Formed: 2 Lone Pairs: 0 Bond Angle: 180o

Trigonal Planar Bonds Formed: 3 Lone Pairs: 0 Bond Angle: 120o

Tetrahedral Bonds Formed: 4 Lone Pairs: 0 Bond Angle: 109.5o

Trigonal Pyramidal Bonds Formed: 3 Lone Pairs: 1 Bond Angle: <109.5o

Bent (Tetrahedral) Bonds formed: 2 Lone Pairs: 2 Bond Angle: <109.5o

Bent (Trigonal Planar) Bonds Formed: 2 Lone Pairs: 1 Bond Angle: <120o

Trigonal Bipyramidal Bonds Formed:5 Lone Pairs: 0 Bond Angle: 120o and 90o

Octahedral Description:6 Lone Pairs: 0 Bond Angle: 900

Molecular Shapes Lab

Molecular Shapes Lab Directions Draw a Lewis Dot Structure for the molecule Make a model using the kit and draw the shape on your paper Write the shape name Write the bond angle Skip POLARITY for now, and we will come back to this part Be careful with the kits, do not drop or lose pieces!

Exit Ticket Draw the Lewis Structure for CO2 Determine the shape and bond angles of CO2 according to the VSEPR theory.

Exit Ticket – Mol Monday # 7 How many formula units of LiCl are in 2.30 moles of LiCl?