* Protons: The number of protons defines the element. In this case, 11 protons means the element is sodium (Na).

* Neutrons: Neutrons contribute to the atom's mass.

* Atomic Mass: The atomic mass is approximately the sum of protons and neutrons.

Calculation:

* Atomic Mass ≈ Protons + Neutrons

* Atomic Mass ≈ 11 + 12

* Atomic Mass ≈ 23

Therefore, the approximate atomic mass of this atom is 23.