Explain why: a) Fluorine is more electronegative than chlorine b)∆H hydration fluoride is more negative than ∆H hydration chloride

a) The fluorine atom is smaller than the chlorine atom, and there is less shielding from other shells of electrons. Thus the bonding pair of electrons are more attracted to the positive nucleus.

b) The fluoride ion is smaller than the chloride ion, giving it a larger charge density. Thus it is more strongly attracted to the delta positive hydrogens on a water molecule.