Answer : An atom with 7 protons, 6 neutrons, and 7 electrons has an atomic mass of 13 amu. Explanation: As we are give that, Number of protons 7 Number of electrons =7 Number of neutrons =6 As we know that, Atomic number =Number of protons = Number of electrons =7 Atomic mass = Number of neutrons + Atomic number Atomic mass = 6 + 7 = 13 amu Therefore, the atomic mass is, 13 amu