What is the nuclear binding energy (in J) for a 56Fe nucleus?

Question

The mass of a proton is 1.673 × 10^-24 g. The mass of a neutron is The mass of the nucleus of an ⁵⁶Fe atom is 9.286 × 10^-23 g. 

Answer 1

56Fe = 26 protons + 30 neutrons + 26 electrons

1). find the mass defect

mass defect = mass of subatomic particles - mass of atom

mass of protons = 26 protons x 1.673x10^-24 g / proton = 4.335x10^-23 g

mass of neutrons = 30 neutrons x 1.675x10^-24 g / neutron = 5.025x10^-23 g

mass of subatomic particles = 4.335x10^-23 g + 5.025x10^-23 g = 9.36x10^-23 g

mass defect = 9.360x100^-23 g - 9.286x10^-23 g = 7.40x10^-25 g = 7.40x10^-28 kg

2). Convert to binding energy

E = binding energy = mc²

E = 7.40x10^-28 kg/nucleus x (2.99x10⁸ m/s)² = 6.62x10^-11 J/nucleus