Question

A specific isotope of an element is known to have 15 protons and 16 neutrons. which symbol would properly represent this isotope

Answer 1

When writing the symbol of an element, the correct way is:

ᵇXₐ

Where b is the mass number of the element, which is equivalent to the sum of the number of protons and neutrons, while a is the atomic number, equal to the number of protons. X is the symbol of the element.

In this case, the atomic number 15 belongs to phosphorus, with symbol P. This becomes:

³¹P₁₅