Question

Question 8 1.2 pts an atom of bromine has a mass about four times greater than that of an atom of neon. which choice makes the correct comparison of the relative numbers of bromine and neon atoms in 1,000 g of each element?

Answer 1

Neon = app. 20.1795 g/mol 
Bromine = app. 79.904 g/mol 
-----> 79.904 g/mol / 20.1795 g/mol = 3.96 (Close to 4) 

Using Moles In 1000 g 

1000 g / 20.1795 g/mol = app. 49.555 mol of Ne 
1000 g / 79.904 g/mol = app. 12.515 mol of Br 
-----> 49.555 mol / 12.515 mol = 3.96 (Close to 4) 

Using Avogadro's Number 

49.555 mol x 6.022x10^23 atoms = app. 2.984x10^25 atoms of Ne 
12.515 mol x 6.022x10^23 atoms = app. 7.537x10^24 atoms of Br 
-----> 2.984x10^25 / 7.537x10^24 = 3.96 (Close to 4) 

So no matter how you look at it or calculate it, the answer is always the same. 

I hope it helps!