Which one of the following elements shows both positive and negative oxidation states? — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

Step 1: Analyze the chemical properties and oxidation state tendencies of each option. Cesium is an alkali metal and only exhibits a +1 oxidation state. Fluorine is the most electronegative element and only shows a -1 oxidation state. Step 2: Xenon is a noble gas and shows only positive oxidation states in its compounds with electronegative elements (like XeF2, XeO3) but does not exhibit negative oxidation states. Step 3: Iodine, being a halogen with lower electronegativity, shows a -1 oxidation state in iodides (e.g., KI) and positive oxidation states (like +1, +3, +5, +7) when bonded to highly electronegative elements like fluorine or oxygen (e.g., IF7, I2O5).