The electronic configuration of four elements are : (I) [Kr] 5s1 (II) [Rn] 5f14 6d1 7s2 (III) [Ar] 3 — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

Step 1: Metallic character corresponds to the ease with which an atom loses its valence electrons (electropositivity). Step 2: Going down a group, atomic size increases and the outer electrons are less tightly bound by the nucleus, resulting in lower ionization energy and increased metallic character. Step 3: Moving from left to right across a period, atomic size decreases and effective nuclear charge increases, making it harder to remove valence electrons. Therefore, metallic character decreases across a period.