They've definitely improved atomic mass and Avogadro's constant. Chemists and students have been fooled into believing they have some special importance but in fact they're nothing more than ugly accidents of history that somehow survived standardization.
We used to have two independently defined mass units! The unified atomic mass unit, and the kg. Now we have only one - the kg, and the other is defined in terms of it.
Avogadro's constant is now clearly identified as an arbitrary number with no illusion of importance since it's no longer part of such an interconnected web of dependencies. Hopefully this will help students to realize that it's not some important chemical quantity but just a way for old people to count big numbers because that's the only way they ever learnt. Nothing more special than the number of feet in a mile.
As for periodic tables not having valid units. They didn't anyway. Chemists, even text-book writers, often neglect to include units for atomic masses. The numerical values will be identical though. The difference is that as we measure them more precisely with future technology, they'll diverge from what they would have been under the old system.
That's a common misconception but all the things that it relates to SI units are themselves redundant. There's an entire parallel system of constants and units built around it which only exists for legacy reasons, as well as people's desire to avoid very big and very small numbers.
If we started from scratch, Avogadro's number would be a simple exact power of 10 or nothing at all and we'd just tolerate extreme numbers the way computer people tolerate terabytes and electronics people tolerate picofarads. There's nothing natural or fundamental about it.
Comments
They've definitely improved atomic mass and Avogadro's constant. Chemists and students have been fooled into believing they have some special importance but in fact they're nothing more than ugly accidents of history that somehow survived standardization.
We used to have two independently defined mass units! The unified atomic mass unit, and the kg. Now we have only one - the kg, and the other is defined in terms of it.
Avogadro's constant is now clearly identified as an arbitrary number with no illusion of importance since it's no longer part of such an interconnected web of dependencies. Hopefully this will help students to realize that it's not some important chemical quantity but just a way for old people to count big numbers because that's the only way they ever learnt. Nothing more special than the number of feet in a mile.
As for periodic tables not having valid units. They didn't anyway. Chemists, even text-book writers, often neglect to include units for atomic masses. The numerical values will be identical though. The difference is that as we measure them more precisely with future technology, they'll diverge from what they would have been under the old system.
Avogadro's number is special because it's what relates fundamental physical constants to SI units.
That's a common misconception but all the things that it relates to SI units are themselves redundant. There's an entire parallel system of constants and units built around it which only exists for legacy reasons, as well as people's desire to avoid very big and very small numbers.
If we started from scratch, Avogadro's number would be a simple exact power of 10 or nothing at all and we'd just tolerate extreme numbers the way computer people tolerate terabytes and electronics people tolerate picofarads. There's nothing natural or fundamental about it.