Which of the following Group 1 elements has the highest ionization energy? By: Sunday|Published on: Aug 22|Categories: Chemistry WAEC| 0 comments A. 55Cs B. 37Rb C. 19K D. 11Na E. 3Li Correct Answer: Option E – 3Li Users Also Read These:Ionization energy increases across the period in the…The two elements 11X and 19Y are in the same group…Moving from left to right across a period; the…Group VII elements are?How are ionization energies related to the…SEE ALSO Which of the following electronic structures belongs to a noble gas?