18. Which of the following give(s) the correct order of ionization energies?
a. Li > Na > K > Rb
b. Na > Mg > P > Cl
c. both a and b
d. neither a nor b
The correct answer is d. neither a nor b.
The correct order of ionization energies is determined by the number of protons in the nucleus, the distance of the electrons from the nucleus, and the shielding effect of inner electrons. Each element has its own unique arrangement of these factors which determines its ionization energy.