He table shows the amount of radioactive element remaining in a sample over a period of time. Radioactive Decay Rate
Amount of Radioactive Sample
(grams) Time
(years)
56.0 0
47.1 400
39.6 800
33.3 1,200
28 1,600

Part 1: What is the half-life of the element? Explain how you determined this.
Part 2: How long would it take 312 g of the sample to decay to 9.75 grams? Show your work or explain your answer.
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catya your not at all which answer i've seen you do this on another question!

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.