Question

Which of the following elements has the largest second ionization energy (IE2)?

Na

Rb

B

F

O

Answer 1

Recall that ionization energy --> energy required to STRIP 1 electron

2nd ionization energy --> eneryg required to strip 2nd electron

Na --> [Ne] 3s1

Rb --> [Kr] 5s1

B --> [He] 2s2 2p1

F --> [He] 2s2 2p5

O --> [He] 2s2 2p4

Note that all of them have plenty of electrons on the valence shell, so stripping 2 electrons should not be "that" difficult

except for:

Na --> [Ne] 3s1

Rb --> [Kr] 5s1

Note that

s1 electron is stirpped easily, but the electron back in the "core" of the electron configuration is much harder, since it is has already octect completion

Between Na and Rb

reall that the further away frm the nucleus, the less attraction from the nucleus is "achieved"

therefore

Choose Na , since the 2nd electorns its pretty near to the nucleus, it will require the MOST energy to strip