9. What do the results tell you about your hypothesis(es)? this is for the lab about density solids for science :)

It must be measured in k.hope my answer is to you : )

Radon-222 or rn-222 has a half-life of 3.82 days. to determine the fraction of an original sample of rn-222 that remains unchanged after 7.646 days, we calculate the amount of rn-222 remaining after 7.646 days and divide it with the original amount. using 1 gram as a basis and using half-life calculation methods, we can determine that  0.249 or 0.25  grams of rn-222 will remain, and thus the fraction remaining is 0.25 or 1/4.

Firstly, the planetary model of the atom  failed  to explain why individual atoms produce discrete  line spectra. in fact, according to rutherford's model, each individual atom should produce a  continuous  line spectrum. the second flaw to his model was the fact that electrons orbit the nucleus in a circular fashion.

Sorry cant answer: c