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# Mass defect and binding energy

Visit us (http://www.khanacademy.org/science/healthcare-and-medicine) for health and medicine content or (http://www.khanacademy.org/test-prep/mcat) for MCAT related content. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video.

## Want to join the conversation?

• Perhaps on future videos, can you guys show it without a calculator like it would be on the MCAT? That way we also get practice with good estimation techniques or rounding.
• These videos were created before making this MCAT playlist... So I doubt it. Also, I guarantee that you will not have to do calculations like this on test day.
• @ will we have to memorize kg/amu? the number? Or mass of a proton/neutron/electron?
• You should probably know the relative masses of protons, neutrons, and electrons, and how to get this info from the periodic table. I suspect that, at @, you would be given this number if it was required.
(1 vote)
• Binding energy is needed to make the nucleus more stable. Does it mean that more the binding energy, the more stable nucleus?
• Indeed! The more energy is released when the individual protons and neutrons combine to form the nucleus, the more stable that nucleus will be. Another way to think about it is that a more stable nucleus would require a larger energy input than a less stable one in order to be split into its constituent particles; this quantity of energy would be equal to the binding energy. :)
• I find this tutor's mic. to always be much quieter than others, so as progressing through videos I switch between hearing next to nothing, turning it up, then blasting my ears out! If you could sound mix it so his volume is on par with others it would be greatly appreciated!