How to Use the Atomic Mass Calculator
Compute mass defect and nuclear binding energy step-by-step:
Enter Protons
Input the atomic number Z (number of protons).
Enter Neutrons
Input the number of neutrons (N) in the nucleus.
Enter Measured Mass
Input actual experimentally measured atomic mass in amu.
Calculate Binding Energy
Get instant mass defect Δm and binding energy per nucleon.
Key Features & Constants
NIST Fundamental Constants
Uses exact proton (1.007276 amu) and neutron (1.008665 amu) rest masses.
Einstein Mass-Energy Relation
Converts amu directly to Mega-electronvolts (1 amu = 931.494 MeV).
Binding Energy Per Nucleon
Measures nuclear stability for nuclear fission and fusion analysis.
Nuclear Physics Guide: Mass Defect & Binding Energy
When individual protons and neutrons coalesce to form a stable atomic nucleus, a fraction of their combined mass is converted into energy released as binding energy. Consequently, the actual bound nuclear mass is always less than the sum of the individual free nucleon masses.
This missing mass is called the mass defect (Δm). According to Einstein's mass-energy equivalence equation \(E = \Delta m \cdot c^2\), this mass deficiency represents the binding energy holding the nucleus together against electrostatic repulsion between positive protons.
Frequently Asked Questions
?Why is binding energy per nucleon important?
Binding energy per nucleon measures overall nuclear stability. Iron-56 (Fe-56) has one of the highest binding energies per nucleon (~8.8 MeV), making it extremely stable.