Bromine (Br) is the only element listed that is a diatomic element. I believe that Bromine is going to be your answer.
After 100years, sample is 250g
After 200 years, sample is 125g
After 300years, sample is 62.5 g
True.
A mixture is composed of two or more pure substance that are physically combined but are not combined chemically and thus no electrons (of their atoms) are involved.
The primary properties of a mixture include:
1. The components of a mixture are easily separated
2. The components each keep their original properties.
3. The proportion of the components may vary.
There are two main categories of mixtures:
1. Heterogeneous mixtures - substances are not evenly distributed e.g. oil and water mixture
2. Homogeneous mixtures - substances are evenly distributed throughout the mixture e.g. salt water, air.
Suspension. The particles are big enough for the eye to see, and will separate if left sitting.
