Question

question 50 (1 point)
of the following elements, which one has the smallest first ionization energy?

a boron
b aluminum
c silicon
d carbon

Explanation:

First ionization energy generally decreases down a group and increases across a period. Boron (B), aluminum (Al), silicon (Si), and carbon (C) are considered. Boron and aluminum are in Group 13, carbon is in Group 14, and silicon is in Group 14. Aluminum is below boron in Group 13. Since ionization energy decreases down a group, aluminum has a lower first ionization energy than boron. Comparing across the period (for elements in the same period, ionization energy increases from left to right), but since we are mainly comparing based on the group trend (as aluminum is lower in its group compared to the others' positions), aluminum will have the smallest first - ionization energy among the given options.

Answer:

B. aluminum