Hello!
A half-life is the amount of time it takes half of an element to decay. For example, after one of carbon's half-life, half of carbon would've decayed.
Now, we can calculate how much has decayed if 5 half lives have passed.
1 -> 50% (1) -> 25% (2) -> 12.5% (3) -> 6.25% (4) -> 3.125% (5)
Therefore, there would be 3.125% left of iodine. However, your question is asking what percent has decayed. Therefore, subtract 3.125 from 100% to get your final answer.
100 - 3.125 = 96.875
Therefore, your final answer is 96.875% of iodine has decayed if 5 half lives have passed.
Hope this helps!
Valence shell
The number of electrons in the outermost shell of a particular atom determines its reactivity, or tendency to form chemical bonds with other atoms. This outermost shell is known as the valence shell, and the electrons found in it are called valence electrons.
B. It was an explanation for how the earth originated.
Answer:
D, but if feel sorry my second guess will be B
