Two of most unique elements on the periodic table are hydrogen and helium. What makes them so unique and removed from the other groups on the periodic table?
Hydrogen and helium are unique because they are the only two elements on the periodic table that are not classified as either a metal or a nonmetal. Hydrogen is the lightest element and helium is the second lightest element, and they are both gases at room temperature. They are also the only two elements that are not affected by chemical reactions, making them chemically inert.
