Answer
He, Fe.
Work Step by Step
Atomic weights: $He: 4.0026 u,\ Fe: 55.845 u,\ Li: 6.94 u,\ Si: 28.085 u,\ C: 12.011 u$
Since the mass is the same (1.0 g), the number of atoms will be inversely proportional to the atomic weights, so the sample with the largest number of atoms is helium, and the one with the smallest is iron.
