40 protons

Is There An Atomic Mass Of 41? Potassium-41 – It has 19 protons and atomic mass is 41. Which atom has an atomic mass of 40? Argon [Ar] has mass number (A) = 40. What element has an atomic mass of 41? Atomic Mass Name chemical element number 92.9064Niobium 41 95.94 Molybdenum 42 98 Technetium