Example of lesson content

April 16, 2016

Disappearing Mass

The mass of a nucleus is less than the mass of the protons and neutrons that it is made of.

(mass of protons + mass of neutrons) – mass of nucleus = ∆m

∆m is the difference in the masses and is called the mass defect.

Let us look at the nucleus of a Helium atom to see this in action. It is made up of 2 protons and 2 neutrons:

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