7. In which pair do both compounds exhibit predominantly ionic bonding? A) RbCl and CaO B) PCI and HF C) KI and 03 D) Na2SO3 and BH3 E) NaF and H₂O 8. For which of the following pairs of species is the difference in radius the greatest? A) C and F B) K* and Br C) Li* and I D) Na and Mg E) 0²- and F 9. A bond in which an electron pair is unequally shared by two atoms is polar covalent. coordinate covalent. ionic. A) B) C) D) nonpolar covalent. E) metallic.