Assertion: neptunium | /r/HasProperty | atomic number
Facets:
Source sentences:
text: Neptunium (Np), radioactive chemical element of the actinoid series of the periodic table that was the first transuranium element to be artificially produced, atomic number 93.
text: Neptunium (chemical symbol Np, atomic number 93) is a silvery radioactive metallic element, belonging to the actinide series.