The best answer is the isotope of strontium which is strontium-85. It has a half-life of about 64 days. The metal strontioum has four stable, naturally occurring isotopes which includes 84Sr (0.56%), 86Sr (9.86%), 87Sr (7.0%) and 88Sr (82.58%).
Answer:
-The mole is appropriate only for counting things that are very small.
-One mole is a very large number of something.
-A molecule of water is much smaller than a grain of sand.
Explanation:
C, a compound because it means it was made up of more than one element but, still able to be separated from the other compound(s)