The melting points of the compounds LiF, NaCl, KBr, and CsI exhibit the following trend:
Melting point order: LiF > NaCl > KBr > CSI
Which of the following correctly explains this trend?
(A) The increasing molar mass requires more energy to melt the substances.
(B) The greater radii of the larger ions results in smaller lattice energies, leading to lower
melting points.
(C) Reactivity increases as you increase the atomic number in the alkali metals. The more
reactive, the easier it is to lose electrons, hence a lower melting point.
(D) The melting point is directly proportional to the electronegative value for the halogen ions
in the compound; there is more attraction for the electrons in the chemical bonds.