When comparing the two elements P and I, the element with the higher first ionization energy is PP When comparing the two elements P and I, the element with the higher first ionization energy is blank based on periodic trends alone. based on periodic trends alone.

The first ionization energy varies in a predictable way across the periodic table. The ionization energy decreases from top to bottom in groups, and increases from left to right across a period. Thus, helium has the largest first ionization energy, while francium has one of the lowest.