chapt10_lec

chapt10_lec - Chapter 10 The Shapes of Molecules 10-1 Dr....

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
10-1 Dr. Wolf’s CHM 101 Chapter 10 The Shapes of Molecules
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
10-2 Dr. Wolf’s CHM 101 The Shapes of Molecules 10.1 Depicting Molecules and Ions with Lewis Structures 10.2 Using Lewis Structures and Bond Energies to Calculate Heats of Reaction 10.3 Valence-Shell Electron-Pair Repulsion (VSEPR) Theory and Molecular Shape 10.4 Molecular Shape and Molecular Polarity
Background image of page 2
10-3 Dr. Wolf’s CHM 101 Lewis Dot Structures A bookkeeping way to keep track of valence electrons and bonding in a molecule. Lines are used to represent a pair of bonding electrons. Dots are used to represent lone pair electrons. In many cases (not H) the octet rule is followed, having eight electrons (including bonding and lone pairs) around each atom. We’ll see later that the octet rule is a natural consequence of having four valence orbitals (s, 3p’s) and the limitation of two electron’s per orbital.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
10-4 Dr. Wolf’s CHM 101 The steps in converting a molecular formula into a Lewis structure. Molecular formula Atom placement Sum of valence e - Remaining valence e - Lewis structure Place atom with lowest EN in center Add A-group numbers Draw single bonds. Subtract 2e - for each bond. Give each atom 8e - (2e - for H) Step 1 Step 2 Step 3 Step 4
Background image of page 4
10-5 Dr. Wolf’s CHM 101 Molecular formula Atom placement Sum of valence e - Remaining valence e - Lewis structure For NF 3 F F F N 5e - F 7e - X 3 = 21e - Total 26e - : : : : : : : N
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
10-6 Dr. Wolf’s CHM 101 SAMPLE PROBLEM 10.1 Writing Lewis Structures for Molecules with One Central Atom SOLUTION: PROBLEM: Write a Lewis structure for CCl 2 F 2 , one of the compounds responsible for the depletion of stratospheric ozone. Step 1: Carbon has the lowest EN and is the central atom. The other atoms are placed around it. C Steps 2-4: C has 4 valence e - , Cl and F each have 7. The sum is 4 + 4(7) = 32 valence e - . Cl Cl F F C Cl Cl F F Make bonds and fill in remaining valence electrons placing 8e - around each atom. : : : : : : :
Background image of page 6
Dr. Wolf’s CHM 101 SAMPLE PROBLEM 10.2 Writing Lewis Structure for Molecules with More than One Central Atom PROBLEM: Write the Lewis structure for methanol (molecular formula CH 4 O), an important industrial alcohol that is being used as a gasoline alternative in car engines. SOLUTION: Hydrogen can have only one bond so C and O must be next to each other with H filling in the bonds. There are 4(1) + 4 + 6 = 14 valence e
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 37

chapt10_lec - Chapter 10 The Shapes of Molecules 10-1 Dr....

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online