Au-198 with half life of 2.7days after after 5.4 days

1/4th the mass of Au-198

Explanation:

A half-life of 2.7 days means that in 2.7 days half of the Au-198 will be gone. This means that after 5.4 days, the amount of Au-198 will have undergone two half-life cycles resulting in there being 1/4th the amount of Au-198 left from the starting amount.

i'm not sure

explanation:

i'll try whatever you got

because u need two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei to form isotopes.

so since they all have the same shape? i mean maybe because m& m and reeses are both chocolates