Assertion: period | /r/MadeOf | technetium
Facets:
value: until lead
type: TEMPORAL
Source sentences:
text: This period contains technetium, one of the two elements until lead that has no stable isotopes (along with promethium), as well as molybdenum and iodine, two of the heaviest elements with a known biological role, and Niobium has the largest magnetic known penetration depth of all the elements.