Consider a sample of helium and a sample of neon, both at 30ºC and 1.5atm. Both samples have a volume of 5.0 liters. Which statement concerning these samples is not true?

Question

a- each weighs the same amount
b- each has the same # of atoms of gas
c- the density of the neon is greater than that of the helium
d- each sample contains the same # of moles of gas
e- none of the above

Well, I thought that the weight is the number under the symbol on the periodic table, which would be 4.003 for helium and 20.18 for neon. And that would make a not true. But I also thought that the number above the symbol on the periodic table is the number of atoms in the element, which would be 2 for helium and 10 for neon. So b would not be true. But I cant have two answers so I have to be wrong somewhere in this thinking...

Answer 1

a is indeed wrong. The number above the atom symbol is the atomic number, the number of protons in the nucleus.
B is true by Avagradros hypothesis
e is wrong also.