Iridium is the most strongest, rarest, densest, expensive, lightest metal ever known
Titanium-Worlds lightest metal Tugasun-aka Heavy stone world heaviest metal
The lightest 'non-metal' could be Hydrogen and Helium! Both are gases, and therefore, not a metal.
The lightest metal is lithium.
Yellow is the weakest therefore its the lightest blue is the strongest.
Lithium is the lightest.
an arch bridge
lithium
Cobalt.
Helium
Lithium is the lightest metal, Potassium is the second lightest -- density about 0.86 kg/L
Lithium is the lightest element metal with a relative atomic mass of 7 (3 protons, 4 neutrons).