Help, please! "A certain radioactive isotope has a half-life of 6 hours. The starting amount is 100 grams. Write an exponential function to model this scenario. How much of the isotope remains after 12 hours?"

I would prefer a step-by-step explanation for both questions, but clean and simple answers would be fine too.

Thanks!

5.52  ×  10^ 3

Step-by-step explanation:

Move the decimal so there is one non-zero digit to the left of the decimal point. The number of decimal places you move will be the exponent on the 10 .  If the decimal is being moved to the right, the exponent will be negative. If the decimal is being moved to the left, the exponent will be positive.