Yeah it uses some valuable scientific vocabulary and background knowledge, I hope this hypothesis will be good enough for your teacher (don't worry it will be)
The number of grams of radon 222 did it have 15.2 ago was 49.6 grams( answer C)
<u>calculation</u>
- calculate the number of half life it has covered from 15.2 days to 3.8 days
that is divide 15.2/ 3.8 = 4 half life
- half life is time taken for a radio activity of a specified isotope to fall to half its original mass
therefore 3.8 days ago it was 3.1 x2 = 6.2 grams
7.6 days ago it was 6.2 x2 = 12.4 grams
11.4 days ago it was 12.4 x2= 24.8 grams
15.2 days ago it was 24.8 x2=49.6 grams
I'm not completely sure but if I did know I would definitely tell u
13
Al
Aluminum
Atomic mass 26.982
