The Pauling electronegativity values for phosphorus and chlorine are 2.19 and 3.16, respectively. Based solely on these values, which classification best describes a single P–Cl bond?
a) Ionic, because ENPENCl=1.44 suggests nearly complete electron transfer
b) Moderately polar covalent, because ΔEN=0.97 falls between typical non-polar and ionic ranges
c) Non-polar covalent, because ΔEN=0.97 is less than 1.0 so the atoms share electrons equally
d) Metallic, because both atoms are in the same period of the periodic table