Answer
See explanation
Work Step by Step
a. Silicon (Si) vs Sodium (Na)
Trend: Ionization energy increases across a period (left to right).
Silicon is to the right of sodium in period 3.
Higher ionization energy: Silicon (Si)
b. Carbon (C) vs Silicon (Si)
Trend: Ionization energy increases up a group.
Carbon is above silicon in group 14.
Higher ionization energy: Carbon (C)
c. Sulfur (S) vs Fluorine (F)
Trend: Ionization energy increases across a period and up a group.
Fluorine is to the right and above sulfur.
Higher ionization energy: Fluorine (F)
