Achloride of this element is 67.2% chlorine by mass. in a 100 g sample how many moles of chlorine are there? (this info will be used to determine the empirical formula. because the accuracy of the result in the last question for this set of questions depends on the accuracy of this answer, use the atomic mass of cl accurate to 4 sig.

1.896 mol Cl

Explanation:

With that information then we can calculate the moles of chlorine present in 67.2 g, using its atomic mass (accurate to 4 sig. fig. as the exercise asked):

67.2 g Cl ÷ 35.45 g/mol = 1.896 mol Cl

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.