Name Period A chemical bond between atoms of different elements is never completely ionic or covalent. The character of the bond depends on how strongly each of the bonded atoms attracts electrons. 1 H 2.1 3 Li 4 Be 1.0 1.5 11 12 Na Mg 0.9 1.2 19 20 Ca 1.0 K 0.8 37 38 Sr 1.0 Rb 0.8 55 Cs 0.7 56 Ba 0.9 87 88 Fr Ra 0.7 0.9 Electronegativity and Bond Character Electronegativity Difference > 1.7 0.3 - 1.7 0 - 0.29 Bond Character Ionic Polar covalent Nonpolar covalent Electronegativity Periodic Table 21 Sc 1.3 39 22 23 24 Cr Ti V 1.5 1.6 1.6 40 41 Nb 42 43 Tc Mo 1.8 1.9 Y 1.2 Zr 1.4 1.6 57 La 1.1 72 Hf 73 Ta 74 75 W Re 1.3 1.5 1.7 89 Ac 1.1 25 Mn 1.5 26 Fe 1.8 44 Ru 2.2 76 Os 1.9 2.2 2.2 27 Co 1.9 28 Ni 1.9 29 Cu 1.9 45 Rh 2.2 46 Pd 47 Ag 1.9 2.2 77 Ir 78 Pt 2.2 79 Au 2.4 5 B 2.0 13 AI 1.5 30 31 Ga Zn 1.6 1.6 48 Cd 49 In Sn 1.7 1.7 1.8 80 Hg 81 TI 1.9 1.8 6 7 C N 2.5 3.0 14 Si 1.8 15 P 2.1 32 Ge 1.8 33 As 2.0 50 51 Sb 1.9 82 Pb 83 Bi 1.9 1.9 8 O 9 F 3.5 4.0 16 17 C S 2.5 3.0 34 Se 2.4 35 Br 2.8 52 Te 53 1 2.1 2.5 84 Po 85 At 2.0 2.2 Electronegativities of the Elements Using your table of electronegativity values to determine what type of bond the two atoms will form. Show the EN calculations and identify which of the three types of bonds is formed. Cl and Br H and F Na and S Br and Br Al and F Cu and Cl How does a polar covalent bond differ from a nonpolar covalent bond?
Name Period For each of the following molecules, determine if it is covalent, polar, or ionic. Show your work by listing the electronegativities of each element in the bond. Molecule H - CI Electronegativity Values Difference in Electronegativity Bond Type H - H H - I Cl - Cl C-0 Ca - 0 H- 0 Al - Fe For each of the following sets of elements, identify the element expected to be most electronegative (EN) and which is expected to be least electronegative (EN). a. K, Sc, Ca b. Br, F, At c. C, O, N most EN= most EN= most EN= least EN= least EN= least EN=