1. Topic: Chemical Bonding
Aim: What are chemical bonds & intermolecular forces?
Do Now: Turn in your review sheet. Scan your notes & write down 5 facts you must know for tomorrow’s test.
HW:

2. Chapter Objectives
Explain energy changes & the relationship to stability
Why bond?
How does energy change?
Explain how chemical bonds are formed
Sharing
Transferring
Mobile e-

3. Chapter Objectives Metallic Mobile sea of e- holds atoms together
Explain conductivity, malleability, luster, ductility

4. Chapter Objectives Ionic bonds Composition – metal & nonmetal
Physical & chemical properties – hard, high mp/bp, conductivity as L or (aq)
Show change in charge when drawing!
Positive ion, lose e-, metals
Negative ion, gain e-, nonmetals

5. Chapter Objectives Covalent Composition – nonmetals
Physical/chemical properties (SPLash)
Single – 2e-, one line
Double – 4e-, 2 lines (O2, CO2)
Triple – 6e-, 3 lines (N2)
Nonpolar covalent (Br, I, N, Cl, H, O, F), equal sharing
Polar covalent (different nonmetals), unequal sharing
Larger difference in electronegativity, more polar
Coordinate covalent (polyatomic ions)
Molecular substances, network solids

6. Chapter Objectives Lewis dot structures Molecular Polarity
To represent ionic – show charges
To represent covalent – show overlap!
Molecular Polarity
Based on shape of molecule & distribution of charge
SNAP – Symmetrical = Nonpolar, Asymmetrical = Polar

7. Chapter Objectives Intermolecular Forces Between molecules
Weaker than bonds
Dipole – between polar covalent mlcls
Partial positive & partial negative charges of neighboring mlcls attract
Hydrogen Bond – between mlcls containing H & either N, O, or F (Ex. NH3, H2O, HF)
Same mechanism as dipole
Strongest IM force

8. Chapter Objectives Van der Waals/Dispersion Forces
Temporary, weak attraction btwn nonpolar mlcls
e- move to 1 side of the molecule, giving it partially charged ends – they stick to one another
Diatomics, noble gases
Larger atom/molecule, stronger dispersion forces (stronger attraction)
Why diatomics & noble gases can be liquified or frozen at low temperatures

9. Chapter Objectives Molecule-Ion Attraction
Why polar substances can dissolve polar & ionic substances – they both have charges
Water (polar) can dissolve other polar or ionic substances (salt, sugar)
Nonpolar in nonpolar
Like dissolves like

10. Chapter Objectives Vapor Pressure & Intermolecular Forces Table H
Weak intermolecular forces – vaporize easily, low boiling point, high vapor pressure
Strong intermolecular forces – difficult to vaporize, high boiling point, low vapor pressure