Polarity The electronegativity values of representative elements in Group 1A 1 to Group 7A 17 Learning Goal Use electronegativity to determine the polarity of a bond Electronegativity ID: 1031392
Download Presentation The PPT/PDF document "6.7 Electronegativity and Bond" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
1. 6.7 Electronegativity and Bond PolarityThe electronegativityvalues of representative elements in Group 1A (1) to Group 7A (17).Learning Goal Use electronegativity to determine the polarity of a bond.
2. ElectronegativityThe electronegativity of an atom is its ability to attract the shared electrons in a bond. Itincreases from left to right going across a period on the periodic table.increases from the bottom to the top of the periodic table.is high for the nonmetals, with fluorine as the highest.is low for the metals.Core Chemistry Skill Using Electronegativity
3. Electronegativity and the Periodic Table
4. Polarity of BondsThe difference in electronegativity of bonding atoms can be used to predict the polarity of the bond.In the H2 molecule, electrons are shared equally and the bond is nonpolar. In the HCl molecule, electrons are shared unequally, and the bond is polar.
5. Nonpolar Covalent BondsA nonpolar covalent bond occurs between nonmetals. Itis an equal or almost equal sharing of electrons by the two bonding atoms.has a very small electronegativity difference between atoms.Examples Electronegativity Atoms Difference Type of Bond N-N 3.0 − 3.0 = 0.0 Nonpolar covalent Cl-Br 3.0 − 2.8 = 0.2 Nonpolar covalent H-Si 2.1 − 1.8 = 0.3 Nonpolar covalent
6. Polar Covalent BondsA polar covalent bond occurs between nonmetal atoms. Itis an unequal sharing of electrons.has a moderate electronegativity difference.Examples Electronegativity Atoms Difference Type of Bond O-Cl 3.5 − 3.0 = 0.5 Polar covalent Cl-C 3.0 − 2.5 = 0.5 Polar covalent O-S 3.5 − 2.5 = 1.0 Polar covalent
7. Dipoles and Bond PolarityA polar covalent bond becomes more polar as the difference in electronegativity increases. The separation of charges in a polar bond is called a dipole.The positive and negative ends of the dipole are located by usingthe lowercase Greek letter delta with a positive or negative charge. an arrow that points from the positive to the negative end of the dipole.
8. Ionic BondsAn ionic bond occurs between metal and nonmetal ions.is a result of electron transfer.has a large electronegativity difference (1.8 or more).Examples Electronegativity Atoms Difference Type of Bond Cl-K 3.0 – 0.8 = 2.2 Ionic N-Na 3.0 – 0.9 = 2.1 Ionic S-Cs 2.5 – 0.7 = 1.8 Ionic
9. Variations in BondingThe difference in electronegativity values for two atoms can be used to predict the type of chemical bond. If the electronegativity difference isbetween 0 and 0.4, the bond is nonpolar covalent.between 0.5 and 1.8, the bond is polar covalent.greater than 1.8, the bond is ionic and the electrons are considered transferred.
10. Electronegativity and Bond Types
11. Predicting Bond Type UsingElectronegativity
12. Study CheckUse the electronegativity difference to identify the type of bond (nonpolar covalent [NP], polar covalent [P], or ionic [I]) between the following:A. K—NB. N—OC. Cl—Cl D. H—Cl
13. SolutionUse the electronegativity difference to identify the type of bond (nonpolar covalent [NP], polar covalent [P], or ionic [I]) between the following: Difference Type of bond A. K—N 2.2 ionic (I) B. N—O 0.5 polar covalent (P)C. Cl—Cl 0.0 nonpolar covalent (NP) D. H—Cl 0.9 polar covalent (P)