Chemical Forums

Specialty Chemistry Forums => Nuclear Chemistry and Radiochemistry Forum => Topic started by: darkouthere on March 27, 2006, 10:40:17 PM

Title: mass of an atom
Post by: darkouthere on March 27, 2006, 10:40:17 PM

Why is the mass of an atom of ⁴He less than the sum of the masses of 2 protons, 2 neutrons, and 2 electrons?

Title: Re:mass of an atom
Post by: Bakegaku on March 27, 2006, 11:35:31 PM

When the nucleons fuse together some of their energy is spent off as bonding energy, so the fused forms are lesser mass than their free forms.  This is why fusion gives off energy.