Trends ionization energy

From Exercise 21-4 we see that the decreasing ionization energies observed for the alkaline earth atoms are readily explained in terms of their increasing size moving down in the periodic table. Notice that the ionization energy trend going down in the periodic table is the same as the trend going to the left in the periodic table. 

Trends in Atomic Size Trends in Ionization Energy Trends in Electron Affinity... 

The radius trend and the ionization energy trend are exact opposites. Does this make sense Define electron affinity. Electron affinity values are both exothermic (negative) and endothermic (positive). However, ionization energy values are always endothermic (positive). Explain. 

Ionization Energy Trends and Resolved Fine Structures... 

The radius trend and the ionization energy trend are exact opposites. Does this make sense Define electron... 

Xenon (Z = 54) was the first noble gas to be chemically combined with another element. Xenon and krypton are present in nearly all of the small number of noble gas compounds known today. Note the ionization energy trend begun with the other noble gases in Figure 11.17. What do these facts suggest about the relative reactivities of the noble gases and the character of noble gas compounds ... 

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