Explanation:
1 mole = 6.02 x 10^23 atoms (Avogadro’s number)
Step 1) Determine how many grams of a substance are in the problem
Step 2) Find the amount of grams in 1 mole of the substance
3) Multiply step one by step two
Because they can live on water and land
Generally speaking the larger, more massive elements are less stable, like isotopes of elements. With this said, they are less likely to react since they will become heavy and unstable. This is why chlorine is more reactive with other elements like sodium than astatine.
Idk but im guessing a. o3