Question: what does the 101 in 256101md represent

The 101 in Md, mendelevium is represents the atomic number, the atomic  symbols of atoms are written featuring the atomic mass as well s the atomic number or number of protons, therefore in ²⁵⁶Md₁₀₁ the 256 is the atomic mass or the number of protons and neutrons while the 101 is the atomic number or simply number of protons or nuclear charge?