Question

3. For each of the following sets of elements, identify the element expected to be the most electronegative and that expected to be the least. a. Li, F, C b. I, CI, F c. Li, Rb, Cs 4. On the basis of electronegativity values given in Figure 11.3, indicate if the following bonds are polar covalent, nonpolar covalent or ionic a. K-N b. Cs- c. C-N d. O-F 5. On the basis of the electronegativity values, indicate which is the more polar bond in each of the following pairs. a. H-For H-CI b. H-Cl or H-1 c. H - Bror H-CI d. H - I or H- Br

Answer 1

(3) We know that alkali metals have less EN and halogens have more electronegativity. (a) Fis most electronegative and Li is least electronegative (b) In a group electronegativity decreases from top to bottom. Fis most electronegative and is least electronegative (c) In a group electronegativity decreases from top to bottom. Li is most electronegative and Cs is least electronegative The nature of the bond depends on the electronegativity of the atoms that are bonded together. If the difference in electronegativity is 0.0 to 0.4, the bond is considered as Non- polar covalent bond. If the difference in electronegativity is 0.5 to 1.7, the bond is considered as Polar covalent bond. If the difference in electronegativity is more than 1.8, the bond is considered as lonic bond. K-N(0.8 – 3.0 = 2.2 ) is lonic bond Cs-0 (0.7 - 3.5 = 2.8 ) is lonic bond C-N ( 2.5 – 3.0 = 0.5 ) is Polar Covalent bond 0-F (3.5-4.0 = 0.5 ) is Polar Covalent bond

(a) Fis more electronegative than Cl. So, H-F bond is more polar bond. (b) Cl is more electronegative than I. So, H-Cl bond is more polar bond. (c) Cl is more electronegative than Br. So, H-Cl bond is more polar bond. (d) Br is more electronegative than 1. So, H-Br bond is more polar bond.