\"give the nuclear symbol for the isotope of gallium, ga, that contains 40 neutrons per atom.\".

The nuclear symbol of the isotopes of gallium where as the symbol must be determined according to its parts and they are the symbol of the element, the atomic number of the element and also the mass number of the specific isotopes. So the symbols is Ga 42 over 71 . I hope this would help

The closer the atoms are to becoming ionic the more highly dense the negatively charged side gets.