Question

1. compare oxygen (o) to selenium (se), choose the most accurate statement, about ionization energy below? a. oxygen has a higher ionization energy because it has a greater shielding effect. b. selenium has a lower ionization energy because it has a greater shielding effect. c. oxygen has a lower ionization energy because it has a greater shielding effect. d. selenium has a higher ionization energy because it has a greater shielding effect.

Explanation:

Ionization energy decreases down a group in the periodic table. Oxygen and selenium are in the same group (Group 16), and selenium is below oxygen. As we move down a group, the out - ermost electrons are further from the nucleus and are shielded by more inner - shell electrons. So, selenium has a lower ionization energy than oxygen because it has a greater shielding effect.

Answer:

C. Oxygen has a lower ionization energy because it has a greater shielding effect.