How many neutrons are present in 5.14g of palladium-105 (isotopic mass = 104.91 amu)?

Question

Correct answer: 1.74E24 neutrons

Can you please provide the steps in obtaining the answer above?

Answer 1

Atomic number Pd = 46 (46 protons)

Number of neutrons = 105 - 46 = 59 neutrons / atom

Number of moles Pd = 5.14 g x 1 mol /104.91 = 0.04899 moles Pd

Atoms of Pd = 0.04899 mols x 6.022x10²³ atoms / mole = 2.950x10²² atoms

Number of neutrons = 2.950x10²² atoms x 59 neutrons / atom = 1.74x10²⁴ neutrons