The findings of henri becquerel and the curies to discredit what notion held for a very long time? that matter can never be created or destroyed. matter is made up of any smaller parts. matter is radioactive and decays over time. that matter is invisible and indestructible.

The answer is: That matter is indivisible and indestructible

Through his experiment, Henri Becquerel found that matters can be stored within another object, (He took potassium uranyl sulfate and put it under the sun and then put the substance within photographic plates that he cover with black paper, ) . Curie found that over time matters would decay and eventually gone.