1. Unit 02 B IMFA, liquids, solids, solutions, colligative properties

2. Intermolecular Attractions Van Der Walls Forces

3. Dispersion Forces Dispersion forces are caused by the movement of electrons Strength of attraction is determined by quantity of electrons Example: Halogen family Chlorine and Fluorine are gases @ STP due to their low number of electrons Bromine has sufficient electrons to produce a liquid @ STP Iodine is solid @ STP

4. Dipole Interactions Dipole interactions are the attraction betweens the opposite poles of polar molecules Hydrogen bonds are a especially strong of dipole interaction

5. Hydrogen Bonding Hydrogen Bonds, the strongest of the intermolecular forces involves the attraction of molecules through the dipole created by the bond between a Hydrogen and a very electronegative atom

6. Colligative Properties The properties of a solution that depend only on the number of solute particles per solvent molecule Molality = moles of solute/kilogram of solvent

7. Freezing Point Depression Freezing point of a solution is lowered with the addition of a solute, usually quite small ∆T f =K f m ∆T f = freezing point depression m=molality, K f =molal freezing point constant

8. Boiling Point Elevation Adding a solute to a solution increases the temp. at which it boils ∆T b =K b m

9. Metallic and Ionic Solids Structure

10. Simple Cubic 1 net atom per unit cell Cell edge = 2r

11. Body Centered Cubic 2 atom per unit cell Cell diagonal = 4r = (√3)(Length of Edge)

12. Face Centered Cubic 4 net atoms per unit cell Cell diagonal = (√2)(length of edge)

13. The End?