Answer: Argon ( Ar )
Explanation: This is element is silicon because it has 18 protons.
***If you found my answer helpful, please give me the brainliest. :) ***
Via the half-life equation we have:

Where A is the amount initially and final amount after some time has passed, t is the time elapsed, h is the half life time and so:

Therefore there will be 2.8125 grams left after 140 seconds.
Cake is a fluffy tasty dessert with frosting, while pie is a crusty, hardish dessert with fillings such as cherries or apples. Can I plz have brainliest?