One of the hypotheses involved in the discovery of radium was:
A) Pure uranium contained an unknown element later known as radium.
B) The intense rays emitted by pitchblende were caused by uranium.
C) The intense rays emitted by pitchblende were caused by impurities in the crystals.
D) It would be possible to produce a radioactive isotope of barium.
E) Mendeleev's periodic table of the elements was incorrect in some respects.

Question

Quizplus · Accepted Answer

The discovery of radium by Marie and Pierre Curie was based on the observation that pitchblende, an ore of uranium, emitted rays that were far more intense than could be explained by the presence of uranium alone. This led them to hypothesize that the intense rays were caused by some other element present as an impurity in the pitchblende, which turned out to be radium.

One of the Hypotheses Involved in the Discovery of Radium