the.com/atomic mass
The weight of an atom, mostly bragged about by its nucleus doing nothing athletic.
means The average mass of an atom of an element, measured in atomic mass units, factoring in the relative abundance of its different isotopes.
from From Greek 'atomos' ('uncuttable') plus 'mass,' itself from Greek 'maza' meaning a lump or barley cake — the word for 'dough' ended up measuring the stuff atoms are made of. 'Atomic mass' as a precise scientific term took shape in the 19th century as chemists like Dalton and Berzelius began weighing elements relative to one another, long before anyone could actually split the 'uncuttable' atom.
- mostly empty
- electrons add charge, barely any mass
- unit origin
- based on carbon-12, arbitrarily crowned the standard
- not whole numbers
- isotopes average out to decimals like 12.011
- mass vs weight
- same atom, same mass, anywhere in the universe