Give the nuclear symbol for the isotope of phosphorus for which a=31? enter the nuclear symbol for the isotope (e. g., 42he).

A = number of mass = 31 = > number of protons + number of neutrons = 31

Phosphours, Z = atomic number = 15 = number of protons

Symbol of the element phosphorus = P

=> The symbol of the isotope is the symbol of the element, P, with the number of mass, 31, to the left, as a superscript, and the atomic number, 15, to the left, as a suscript.