* Gallium's Atomic Number: Gallium (Ga) has an atomic number of 31. This means every gallium atom has 31 protons.
* Neutrons and Isotopes: The number of neutrons can vary in an element, creating isotopes. The isotope with 39 neutrons is an uncommon one for gallium.
* Calculating Atomic Mass: Atomic mass is the sum of protons and neutrons in an atom's nucleus.
* Atomic Mass = Protons + Neutrons
* Atomic Mass = 31 + 39 = 70
Therefore, the atomic mass of gallium with 39 neutrons is 70 atomic mass units (amu).
