Sodium - reacts vigorously with water. magnesium - shiny, silvery, soft metal. chlorine - forms an acid when combined with hydrogen. xenon - colorless and odorless gas. look at the periodic table and the characteristics of the elements given above. select the group of elements that include only those that are either colorless, odorless gases or shiny, silvery, soft metals. a) radon, neon, calcium b) neon, bromine, barium c) beryllium, iodine, krypton d) lithium, potassium, fluorine