Lewis Diagrams (College Board AP Chemistry)

Some binary compounds that form between fluorine and various nonmetals are listed in the table above. A student examines the data in the table and poses the following hypothesis: the number of F atoms that will bond to a nonmetal is always equal to 8 minus the number of valence electrons in the nonmetal atom.

Based on the student’s hypothesis, what should be the formula of the compound that forms between chlorine and fluorine?

In an attempt to verify the hypothesis, the student researches the fluoride compounds of the other halogens and finds the formula ClF₃ . In the box below, draw a complete Lewis electron-dot diagram for a molecule of ClF₃ .

Two possible geometric shapes for the ClF₃ molecule are trigonal planar and T-shaped. The student does some research and learns that the molecule has a dipole moment. Which of the two shapes is consistent with the fact that the ClF₃ molecule has a dipole moment? Justify your answer in terms of bond polarity and molecular structure.

In an attempt to resolve the existence of the ClF₃ molecule with the hypothesis stated above, the student researches the compounds that form between halogens and fluorine, and assembles the following list.

Based on concepts of atomic structure and periodicity, propose a modification to the student’s previous hypothesis to account for the compounds that form between halogens and fluorine.