The third period contains only 8 electrons and not 18 like 4th period. — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

Step 1: Identify which elements exist in the liquid state at room temperature. Mercury (Hg) is the liquid metal, and Bromine (Br) is the liquid non-metal. Step 2: Find the atomic numbers of these elements. Mercury has Z=80 and Bromine has Z=35. Step 3: The question asks for the metallic element's atomic number followed by the non-metallic element's atomic number, which yields the pair 80 and 35.