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Learn about covalent bonding, polar bonds, and molecules in this informative guide. Understand the concept of bond polarity, classifications for bonds, and the electronegativities of atoms. Explore examples of polar and nonpolar molecules and discover how structure determines polarity. Three video clips will further enhance your understanding.
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Covalent Bonding Polar Bonds and Molecules
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 Bonds • Nonpolar covalent • When atoms pull the bond equally • Happens with two atoms of equal electronegativity, most often using the same atoms • Examples: H2, O2, N2 • Polar covalent • When atoms pull the bond unequally • Happens with two atoms of different electronegativities • Example: HCl, HF, NH
Covalent Bonding-- Polar Bonds and Molecules -- Bond Polarity • In 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.
Covalent Bonding-- Polar Bonds and Molecules -- Bond Polarity • Electronegativities and Bond Types • H: 2.1 Cl: 3.0 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.
Covalent Bonding-- Polar Bonds and Molecules -- Polar Molecules • Dipole • Molecule that has two poles • Example: HCl from the previous page • Polar vs. Nonpolar • H2O and CO2 • Both have 3 atoms; yet, • One is polar and one is nonpolar. • Why? • Structure (with bond polarity) determines the molecules polarity.