2.42 An element with mass number 81 contains 31.7% more neutrons as compared to protons. Assign the atomic symbol.
Let the number of protons of an atom be .
Then the number of neutrons will be,
and the mass number is (Given).
Mass number = number of neutrons + number of protons.
Therefore,
Thus, there are numbers of protons which is also its atomic number.
Hence, the symbol for the element is .