11. Why is the first ionization energy of a nonmetal much higher than that of an alkali metal in its same period

Well, nonmetals have more filled shells, making it harder to remove electrons, AND n onmetals have smaller atoms, while metals have larger atoms and therefore less attraction of the electrons to the nucleus. The nuclear charge increases from left to right across a period and the shielding effect stays the same. So it is more difficult to remove an electron from a nonmetal than an alkali metal.; 3