To determine the mass of oxygen per gram of sulfur for sulfur dioxide, we simply obtain the ratio of the mass of oxygen and the mass of sulfur produced from the decomposition of sulfur dioxide. All other values given in the problem statement above are just to confuse us that the question is a difficult one. We do as follows:
mass of oxygen per gram sulfur = 3.45 g / 3.46 g
mass of oxygen per gram sulfur = 0.9971 g O2 / g S
First, we will get the "n", the number of half lives, it is the elapsed time over the half life. In the problem, the time is measured in days, so we have
6/2 = 3
to get the ending amount of radioactive sample, we have
32g x (1/2)³ = 4 grams of radioactive sample ⇒ the amount left after 6 days
Row or periods have in common is the valence electron count. The valence electron count goes up as you move across the periodic table. Also atomic size gets smaller as you move from left to right