To calculate the approximate atomic mass of an atom, we add the number of protons and neutrons together. In this case, the atom contains 11 protons and 12 neutrons.
The atomic mass is given by the sum of the masses of the protons and neutrons in atomic mass units (amu). The atomic mass of a proton is approximately 1.00784 amu, and the atomic mass of a neutron is approximately 1.00867 amu.
Therefore, the approximate atomic mass of the atom with 11 protons and 12 neutrons would be:
Atomic mass ≈ (11 protons × 1.00784 amu/proton) + (12 neutrons × 1.00867 amu/neutron)
Atomic mass ≈ 11.08624 amu + 12.10404 amu
Atomic mass ≈ 23.19028 amu
Hence, the approximate atomic mass of the given atom is approximately 23.19028 atomic mass units.