Final answer:
In Part A, Kr has the highest first ionization energy. In Part B, Na has the highest first ionization energy. In Part C, Rn has the highest first ionization energy. In Part D, Sb has the highest first ionization energy.
Step-by-step explanation:
In Part A, the element with the highest first ionization energy is Kr. The first ionization energy is the energy required to remove an electron from an atom. Kr has a higher first ionization energy than Br because it is a noble gas located in Group 18 of the periodic table, meaning it has a full electron shell and is more stable than Br.
In Part B, the element with the highest first ionization energy is Na. Na has a higher first ionization energy than Rb because Na is smaller in size and has a stronger attraction between the positively charged nucleus and the negatively charged electrons, making it more difficult to remove an electron from Na.
In Part C, the element with the highest first ionization energy is Rn. Rn has a higher first ionization energy than Pb because Rn is a noble gas located in Group 18 of the periodic table, meaning it has a full electron shell and is more stable than Pb.
In Part D, the element with the highest first ionization energy is Sb. Sb has a higher first ionization energy than S because Sb is smaller in size and has a stronger attraction between the positively charged nucleus and the negatively charged electrons, making it more difficult to remove an electron from Sb.