Presentation is loading. Please wait.

Presentation is loading. Please wait.

I. Bond Polarity and IMF (237 – 241)

Similar presentations

Presentation on theme: "I. Bond Polarity and IMF (237 – 241)"— Presentation transcript:

1 I. Bond Polarity and IMF (237 – 241)
Ch. 8 – Covalent Compounds I. Bond Polarity and IMF (237 – 241)

2 A. Bond Polarity Most bonds are a blend of ionic and covalent characteristics Difference in electronegativity determines bond type

3 A. Bond Polarity Electronegativity
Attraction an atom has for a shared pair of electrons higher e-neg atom  - lower e-neg atom + Draw the Lewis structure for HCl & label partial charges

4 A. Bond Polarity Electronegativity Trend (p. 178)
Increases up and to the right

5 A. Bond Polarity Nonpolar Covalent Bond e- are shared equally
symmetrical e- density usually identical atoms

6 + - A. Bond Polarity Polar Covalent Bond e- are shared unequally
asymmetrical e- density results in partial charges (dipole) + -

7 A. Bond Polarity Determine bond polarity: C – O Ca – O PC
Si – Cl H – F N – N 3.44 – 2.55 = 0.89 3.44 – 1.00 = 2.44 3.16 – 1.90 = 1.26 3.98 – 2.20 = 1.78 3.04 – 3.04 = 0.00 PC Ionic NPC

8 A. Bond Polarity Nonpolar Polar Ionic View Bonding Animations.

9 B. Molecular Polarity Polar molecule = one end slightly + and one end slightly – Molecule with 2 poles = dipolar molecule or dipole

10 B. Molecular Polarity Shape, symmetry and bond polarity determines molecular polarity H – O bond is polar and water is asymmetrical, so H2O is polar C – Cl bond is polar, but CCl4 is symmetrical, so molecule is nonpolar

11 B. Molecular Polarity Identify each molecule as polar or nonpolar SCl2
CS2 CF4 CH2F2 Tetrahedral, bent → polar Nonpolar bonds → nonpolar Linear → nonpolar Tetrahedral → nonpolar Tetrahedral → polar

12 C. Definition of IMF IMF = Intermolecular Forces
Attractive forces between molecules Much weaker than chemical bonds within molecules

13 D. Types of IMF Van der Waals

14 D. Types of IMF London Dispersion Forces View animation online.

15 D. Types of IMF Dipole-Dipole Forces + - View animation online.

16 D. Types of IMF Hydrogen Bonding

17 E. Determining IMF PCl3 polar = dispersion, dipole-dipole CH4
nonpolar = dispersion HF H-F bond = dispersion, dipole-dipole, hydrogen bonding

18 F. Network Solids Substances in which all atoms are covalently bonded to each other Very stable Examples Diamonds – Carbon covalently bonded to carbon Quartz – SiO2 covalently bonded and not distinct molecules

19 Ch. 7 – Ionic Bonds & Properties
II. Ions (p. 194 – 200)

20 A. Formula Unit The lowest whole-number ratio of ions in an ionic compound

21 B. Ionic Bonds Oppositely charged ions attract, force that holds them together = ionic bond Electrons are transferred from cations to anions Bonds formed between metals and nonmetals (or contain a polyatomic ion)

22 B. Properties of Ionic Compounds
Most ionic compounds are crystalline solids at room temp Ionic compounds generally have high melting points Large attractive forces result in very stable structures

23 III. Bonding in Metals (p. 201 – 203)
Ch. 7 – Ionic and Metallic Bonding III. Bonding in Metals (p. 201 – 203)

24 A. Metallic Character Metals Nonmetals Metalloids

25 B. Metals good conductors because the valence electrons are able to flow freely Valence electrons of metals can be thought of as a sea of electrons Properties can be explained by the mobility of electrons in metals

26 C. Metallic Bond Metallic Bonding - “Electron Sea”

27 D. Metallic Properties Properties can be explained by the mobility of electrons in metals When subjected to pressure , the cations easily slide past each other like a ball bearing immersed in oil

28 E. Summary METALLIC e- are delocalized among metal atoms
Bond Formation e- are delocalized among metal atoms Smallest Unit “electron sea” Physical RT solid Melting Point very high

Download ppt "I. Bond Polarity and IMF (237 – 241)"

Similar presentations

Ads by Google