Answer:
i am not sure i think they sound the same
Explanation:
Halogens (atoms with 7 valence electrons) and Hydrogen
or generally, atoms with their shells almost full
The answer is 1/16.
Half-life is the time required for the amount of a sample to half its value.
To calculate this, we will use the following formulas:
1.
![(1/2)^{n} = x](https://tex.z-dn.net/?f=%20%281%2F2%29%5E%7Bn%7D%20%3D%20x)
,
where:
<span>n - a number of half-lives
</span>x - a remained fraction of a sample
2.
![t_{1/2} = \frac{t}{n}](https://tex.z-dn.net/?f=%20t_%7B1%2F2%7D%20%3D%20%5Cfrac%7Bt%7D%7Bn%7D%20)
where:
<span>
![t_{1/2}](https://tex.z-dn.net/?f=%20t_%7B1%2F2%7D%20)
- half-life
</span>t - <span>total time elapsed
</span><span>n - a number of half-lives
</span>
So, we know:
t = 10 min
<span>
![t_{1/2}](https://tex.z-dn.net/?f=%20t_%7B1%2F2%7D%20)
= 2.5 min
We need:
n = ?
x = ?
</span>
We could first use the second equation to calculate n:
<span>If:
![t_{1/2} = \frac{t}{n}](https://tex.z-dn.net/?f=%20t_%7B1%2F2%7D%20%3D%20%5Cfrac%7Bt%7D%7Bn%7D%20)
,
</span>Then:
![n = \frac{t}{ t_{1/2} }](https://tex.z-dn.net/?f=n%20%3D%20%5Cfrac%7Bt%7D%7B%20t_%7B1%2F2%7D%20%7D%20)
⇒
![n = \frac{10 min}{2.5 min}](https://tex.z-dn.net/?f=n%20%3D%20%5Cfrac%7B10%20min%7D%7B2.5%20min%7D%20)
⇒
![n=4](https://tex.z-dn.net/?f=n%3D4)
<span>
</span>
Now we can use the first equation to calculate the remained fraction of the sample.
<span>
![(1/2)^{n} = x](https://tex.z-dn.net/?f=%20%281%2F2%29%5E%7Bn%7D%20%3D%20x)
</span>⇒
![x=(1/2)^4](https://tex.z-dn.net/?f=x%3D%281%2F2%29%5E4)
<span>⇒
![x= \frac{1}{16}](https://tex.z-dn.net/?f=x%3D%20%5Cfrac%7B1%7D%7B16%7D%20)
</span>
D) Radioactive contamination
ADD THEM all, and then divide by four. Thats what I would do!