I believe it is D as you are hearing the copper tube
Yeah it depends on what mixture
It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Na-24 (Sodium, atomic number Z = 11, mass number A = 24).
The first one is correct cause first of all it's atomic number is 7 and second of all it's atomic mass is about 15
