Predict which species in each of the following pairs has the higher first ionization energy.

(a) Mg or P

(b) B or Cl

(c) K⁺ or Ca²⁺

Strategy

Use the ionization energy trends—

(1) Up a group, the ionization energies increase;

(2) Across a row from left to right, ionization energies mainly increase—to determine which has the greater ionization energy. For two species that are isoelectronic, the species with the greater charge has the higher ionization energy. Use the small periodic table shown to locate the elements.

Transcribed Image Text:

Mg K Ca B P CI