The atomic mass of an atom can be determined by adding the number of protons and neutrons together. In this case, the atom has 6 protons and 6 neutrons.
Atomic mass = number of protons + number of neutrons
Atomic mass = 6 protons + 6 neutrons = 12.
Although electrons are also part of the atom, they do not significantly contribute to the atomic mass because their mass is negligible compared to protons and neutrons. Therefore, the atomic mass of this atom is 12 atomic mass units (amu).