Polar Bonds and Molecules Snow covers approximately 23

Polar Bonds and Molecules Snow covers approximately 23 percent of Earth’s surface. Each individual snowflake is formed from as many as 100 snow crystals. The polar bonds in water molecules influence the distinctive shape of snowflakes.

8. 4 Bond Polarity Bonding Ionic Covalent Polar Nonpolar

nonpolar covalent bond: atoms in a bond have equal pull so the bonding electrons are shared equally. H 2, N 2, O 2, F 2, Cl 2, Br 2, I 2 H H

nonpolar covalent bond:

polar covalent bond: bonding electrons are shared unequally. H-Cl, H-F, O-H, C-N less EN + “partial” H Cl more EN dipole: molecule with one end slightly –, the other end slightly + making 2 poles.

8. 4 Polarity F is. Bond a 4. 0 (most EN element) C–H is the only NONpolar bond between two different atoms

Bonding Summary Ionic (e- transferred) Polar Covalent (e- unequally shared) Nonpolar Covalent (e- equally shared)

polar molecule: has a net dipole since the polar bonds do not cancel out. (SHAPE matters) (HCl, H 2 O, NH 3)

nonpolar molecule: has NO net dipole since the polar bonds cancel out. (SHAPE matters) (CO 2, CCl 4, Cl 2)

Quick Quiz! 1. In a nonpolar covalent bond, electrons are A. gained by one atom. B. shared unequally between atoms. C. shared equally between atoms. D. lost by both atoms. Give 2 example of nonpolar molecules: Br 2, CO 2, CCl 4

Quick Quiz. 2. + In a molecule, the most electronegative atom A. repels electrons more strongly and acquires a partial negative charge. B. repels electrons more strongly and acquires a partial positive charge. C. attracts electrons more strongly and acquires a partial positive charge. D. attracts electrons more strongly and acquires a partial negative charge.

Quick Quiz. 3. Which of the following bonds is the most polar? A. H-N B. O-N C. H-F D. Cl-Cl greatest difference in EN

Quick Quiz. 4. Why is carbon tetrachloride, CCl 4, a nonpolar molecule even though it contains 4 polar C–Cl bonds? A. The polar bonds are too weak. B. The polar bonds cancel in opposite directions. C. Carbon is always nonpolar. D. Carbon tetrachloride has single bonds.

Quick Quiz. 5. Which of the following is a polar molecule? A. H 2 S B. CO 2 C. NH 3 D. I 2 S