Assertion: actinium's life | /r/HasProperty | the time
Facets:
Source sentences:
text: One half-life is the time required for one half of any given quantity of the substance to decay.
text: The half life of a radioactive element is the time it takes for half of a sample of the element to break down.
text: The half life of a radioactive element is the time it takes for half of a sample of the element to break down.