Mass defect for helium atom: (1 Viewer)

[umm what]

Where did they get the rest masses from?

 

[umm what]

^^ anyone?

 

[Fizzy_Cyst]

I would say they got it from the Physics HSC Data sheet and just converted it into atomic mass units using the conversion factor, which is also on the data sheet

 

[mark120]

that information would be found in the periodic table. The rest mass of He is 4.003 in the table we get in the HSC