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. in their respective periods due to stable closed-shell electronic configurations. Step 2: Compare Helium (He) and Neon (Ne). Helium is in the 1st period and Neon is in the 2nd period. Step 3: Because Helium is smaller in size, its electrons are closer to the nucleus and held much more tightly. Helium thus possesses the highest first ionization potential in the entire periodic table.