Periodic Table What is the chemical symbol for gold? Au Gd Pt Hg None Which element is the most abundant in Earth's crust? Oxygen Silicon Aluminum Iron None What is the lightest noble gas? Helium Neon Argon Krypton None Which element is essential for the process of photosynthesis in plants? Carbon Nitrogen Phosphorus Chlorine None What is the chemical symbol for mercury? Hg Me Mn Mg None Time's up Most Popular Most Popular
