Question

Based on electronegativity values, would you expect the individual bonds in BF_3 and NH_3 polar? (A table of electronegativity values can be found on p. 191 of the textbook.) B-F (yes/no) N-H (yes/no) Which bond should be more polar, B-F or N-H? In the boxes below, sketch each molecule and label all the atoms with delta+ or delta- to indicate the sign of the partial charge on every atom. Use the molecular geometries from part A, along with the concept of vector summation, to predict whether the BF_3 and NH_3 molecules should be polar. Run the "Molecule Polarity" simulation (Figure 2). Click on the Real Molecules tab at the top and click the checkboxes in the View dialogue to show the bond dipole vectors, the summation vector for the molecule, and the partial charges. Do the signs of the partial charges agree with the signs that you assigned to the atoms in your sketches in #1 above? If not, try to explain the difference. BF_3 (yes/no) NH_3 (yes/no)

Answer 1