No, shared values is referring to the moral/emotional stuff, I find it more useful when trying to bridge the gap in a pretty politically charged environment to reconnect on simple things like wanting other people to be happy and healthy.

Are those true things? Good candidates, I like 'leptons exist'. Do you mind if we just gently ignore the math one? Feels like inviting the whole 'is math invented or discovered' thing.

1) carbon atoms in a mol - a mol is a counting number so it seems tautological to declare this one a truth

2) pass :)

3) this seems like a good candidate but it also seems to reduce truth to just the things we measure and only to the extent that we can be accurate (I'm also assuming you meant neutrons, protons are static by specie). Purely hypothetically there could be a whole heap of unusually heavy or light carbon out there that would disprove one or another of our theories. To put it another way; is the average number of apples that a trees grows in a year 'true'? It'll change year after year after all. I'm fine with a definition of truth that implies error bars and best efforts but I feel it falls short of the colloquial definition.

4) I think the pure observation that a thing somewhere exists is probably the closest to true, the rebuttals against that would all be self consuming anyway. The specific claim that leptons exist seems a little more fraught though - we could conceivably come to another conclusion if that better fit the facts.

So, can we call these things true if our concept is potentially incomplete or incorrect?