Hi. Assuming you’re talking about solid elements:
(specific heat capacity) x (atomic mass) = 3R where R is the universal gas constant. This is Dulong-Petit law. And it’s an approximate law.
The value of R will of course vary depending on what units you want specific heat capacity in, but for specific heat in J/(g-C) and atomic mass in g/mol R is 8.31 J/(mol-K).
So, in that case, specific heat x atomic mass = 3x8.31 = 24.94.
As an example, you could check this with aluminum. molar mass 26.98 g/mol.
So, Csp x (26.98 g/mol) = 24.94 J/mol-K.
Csp = 0.924 J/g-K.
Reported specific heat is 0.902 J/(g-K)
As another example you could check copper. Atomic mass 63.55 g/mol:
So, Csp x (63.55 g/mol) = 24.94 J/mol-K.
Csp = 0.392 J/g-K.
Reported specific heat is 0.385 J/(g-K)
Hope that helps.