Defeito de Massa
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
The mass defect calculator determines the difference between the theoretical mass of an atomic nucleus (based on the sum of proton and neutron masses) and the experimentally measured mass. This concept is essential in nuclear physics to analyze the binding energy between subatomic particles.
The formula used is Δm = (Z·mp + N·mn) − m_nucleus, where Z is the atomic number (protons), mp is the proton mass, N is the neutron count, mn is the neutron mass, and m_nucleus is the measured nucleus mass. The resulting mass defect (Δm) corresponds directly to the energy released during nucleus formation, as described by Einstein's E = Δm·c² equation.
This tool is applied in nuclear fission studies, stellar fusion modeling, and reactor development. It's crucial to remember that free proton and neutron masses differ from those within a nucleus due to binding forces. Accurate atomic mass values are required for reliable results.
For meaningful outcomes, consult approved atomic mass tables (like IUPAP) and ensure the calculator uses updated values. Mass defect also helps estimate isotope stability and predict viable nuclear reactions.
Frequently asked questions
What is the purpose of calculating mass defect?
It determines the nuclear binding energy related to energy released in nuclear reactions.
Why is the actual nucleus mass less than the theoretical value?
Because some mass is converted into energy during nucleus formation, as per E = Δm·c².
What data is required to use this calculator?
You need the atomic number (Z), neutron count (N), and masses of proton, neutron, and measured nucleus.
How to interpret the mass defect value?
Higher mass defect indicates stronger binding energy and greater nucleus stability.
Can mass defect be negative?
No. A negative result indicates input errors or inaccuracies in mass values.