Answer:
atom is the smallest unit of matter that has the characteristic properties of a chemical element.
Answer:
7.6 days
Explanation:
Radon is a radioactive element and Radon-222 is it's most stable isotope. The half-life of Radon-222 has been found to be approximately 3.8 days.
Let, the initial amount of the Rn-222 = 1 = A
Final amount =
= A'
We will use the following relation for calculating time elapsed in the decay

Thus,

We can write is as,

Since the base in both sides are equal, powers can also be equal and thus,

So, t = 7.6 days
Sand is because the other ones are liquid
I am pretty sure it is Vitamin A... but I could be wrong. Sorry if it is wrong.