What kinds of information about the atomic structure of an elements can you learn from the Periodic Table?

Nuclear fusion is the source of energy for stars. besides hydrogen, which other element is most likely also common in stars?

How many mmols of tris-hcl are there in 100 ml of a 100 mm tris-hcl buffer solution at ph 8.1? note that the 100 mm refers to the sum of tris and tris-hcl concentrations?

Avariable that is not being directly tested during an experiment should be