Element having highest I.P. value is : — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

Step 1: Ionization potential (I.P.) generally increases across a period and decreases down a group. Noble gases have the highest I.P. values due to stable closed-shell electronic configurations. Step 2: Compare the noble gases Helium (He, 1st period) and Neon (Ne, 2nd period). Step 3: Because Helium is smaller, its valence electrons are much closer to the nucleus and held with stronger electrostatic attraction, giving Helium the highest first ionization potential in the entire periodic table.