Final answer:
The nuclear symbol for the isotope of gallium that contains 40 neutrons per atom is 69Ga.
Step-by-step explanation:
The nuclear symbol for the isotope of gallium that contains 40 neutrons per atom is 69Ga.
When writing the nuclear symbol, the mass number is represented as a superscript to the left of the element symbol and the atomic number (number of protons) is represented as a subscript to the left of the element symbol. In this case, the mass number is 69 and the atomic number is 31, giving us 6931Ga.