Answer:
The right answer is "3 g".
Explanation:
Given:
Initial mass substance,

By using the relation between half lives and amount of substances will be:
⇒ 


Thus, the above is the correct answer.
Protons .because electron has negative charge and proton has positive charge.
84 divided by 2 = 42.
2 goes into 8 four times, so there would be your 4.
Then 2 goes into 2 one time, and there would be your 2.
You check your answer by multiplying 42 by 2, which would give you, 84.