Presentation on theme: "Polar Bonds and Molecules"— Presentation transcript:
1 Polar Bonds and Molecules Covalent BondingPolar Bonds and Molecules
2 Covalent Bonding -- Polar Bonds and Molecules -- Bond Polarity“The Tug of War”The pairs of electrons that are bonds between atoms are pulled between the nuclei of the atoms in a bond.The electronegativities of the atoms determine the winner.Classifications for BondsNonpolar covalentWhen atoms pull the bond equallyHappens with two atoms of equal electronegativity, most often using the same atomsExamples: H2, O2, N2Polar covalentWhen atoms pull the bond unequallyHappens with two atoms of different electronegativitiesExample: HCl, HF, NH
3 Covalent Bonding -- Polar Bonds and Molecules -- Bond PolarityIn a polar molecule, one end of the molecule is slightly more electronegative than the other atom, resulting in one atom being slightly negative (-) because of higher electronegativitiy, and the other atom being slightly positive (+) because of lower electronegativity. is known as a partial charge since it is much less than 1+ or 1- charge.
4 Covalent Bonding -- Polar Bonds and Molecules -- Bond PolarityElectronegativities and Bond TypesH: Cl: Since hydrogen is less, it will have the positive partial charge while chlorine has the negative partial charge.3.0 – 2.1 = 0.9 HCl is polar covalent.0.0 – 0.1 differenceNonpolar covalent bondH – H (0.0 difference)0.1 – 1.7 differencePolar covalent bondH – Cl (0.9 difference)1.7 + differenceIonic bondNa+Cl- (2.1 difference)
5 Covalent Bonding -- Polar Bonds and Molecules -- Polar MoleculesDipoleMolecule that has two polesExample: HCl from the previous pagePolar vs. NonpolarH2O and CO2Both have 3 atoms; yet,One is polar and one is nonpolar.Why?Structure (with bond polarity) determines the molecules polarity.