Question

i am a noble gas. you wont find a member in my family that is lighter than me. who am i? view periodic table tap on an option below to select or deselect an answer. helium (he) lithium (li) beryllium (be) scandium (sc) boron (b) radon (rn) oxygen (o) hydrogen (h) fluorine (f)

Explanation:

First, eliminate non-noble gases: Lithium (Li), Beryllium (Be), Scandium (Sc), Boron (B), Oxygen (O), Hydrogen (H), Fluorine (F) are not noble gases. Among the remaining options, Helium (He) is the lightest noble gas (lowest atomic mass, ~4.003 u), with no lighter noble gas existing above it in the periodic table's noble gas group. Radon (Rn) is a heavy noble gas, so it is not the lightest.

Answer:

Helium (He)