Electronegativity (EN): relative ability of an atom to attract electrons in a bond to itselfElectronegativity TrendsElectronegativity increases moving up, to the right in the periodic table (omitting the noble gasses)Ionization Energies and ElectronegativityIncreases across a rowDecreases down a columnPolar Covalent Bonds- unequal sharing of bonding par of electrons between atomsResults in uneven distribution of chargeBond Polarity- a measure of the extent to which bonding electrons are unequally shared due to differenced in electronegativity of the bonded atomsBond PolarityPolar bondPartial negative and positive chargesDirection of polarity indicated by arrow pointing to more negative end of bond, with + sign at positive endDegree of polarity depends on differences in electronegativity**Bond polarity increases as ΔEN increasesDo Electronegativity Differences Indicate an Ionic vs. Covalent Compound?Generally guidelines can be found that say:ΔEN ≤ 0.4 Nonpolar covalentΔEN 0.4 – 2.0 polar covalentΔEN ≥ 2.0 IonicHowever. . . . Let us consider:Gold (I) Iodide(Aul) ΔEN = 0.1Magnesium Sulfide (MgS) ΔEN=1.3Silicon tetraflouride (SiF4) ΔEN= 2.2CHEM 111 1nd Edition Lecture 15 Outline of Last Lecture I. Binary AcidsII. OxoacidsIII. Lewis StructuresIV. Multiple BondsOutline of Current Lecture II. ElectronegativityIII. Polar Covalent BondsIV. Bond PolarityV. Electronegativity DifferencesCurrent Lecture Electronegativity (EN): relative ability of an atom to attract electrons in a bond to itself Electronegativity Trends- Electronegativity increases moving up, to the right in the periodic table (omitting thenoble gasses)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. Ionization Energies and Electronegativity - Increases across a row- Decreases down a column Polar Covalent Bonds- unequal sharing of bonding par of electrons between atoms- Results in uneven distribution of charge Bond Polarity- a measure of the extent to which bonding electrons are unequally shared due to differenced in electronegativity of the bonded atoms Bond Polarity Polar bond- Partial negative and positive charges- Direction of polarity indicated by arrow pointing to more negative end of bond, with + sign at positive end- Degree of polarity depends on differences in electronegativity **Bond polarity increases as ΔEN increases Do Electronegativity Differences Indicate an Ionic vs. Covalent Compound? Generally guidelines can be found that say:ΔEN ≤ 0.4 Nonpolar covalentΔEN 0.4 – 2.0 polar covalentΔEN ≥ 2.0 Ionic However. . . . Let us consider: Gold (I) Iodide(Aul) ΔEN = 0.1 Magnesium Sulfide (MgS) ΔEN=1.3 Silicon tetraflouride (SiF4) ΔEN=
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