The nuclear symbol of an element have three parts namely:
- the symbol of an element
- mass number of the element
- atomic number of the element
The general representation is as:
where X is the chemical symbol of the element, A is mass number of the element that is total number of neutrons and protons in the nucleus of an atom, and Z is atomic number of the element that is number of protons in the atom.
Element = Gallium, (given)
Number of neutrons = 40 (given)
Let the nuclear symbol be . So, we need to determine the values of "?" in the symbol.
Atomic number of Gallium, = 31
Since, atomic number = Number of protons.
So, number of protons of Gallium, = 31
Mass number = number of protons + number of neutrons
Substituting the values:
Mass number =
So, the nuclear symbol is .