Question

What isotope has $14$ protons and $14$ neutrons?

Answer 1

Isotopes are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number. All isotopes of a given element have the same number of protons but different numbers of neutrons in each atom.

Complete answer:
For any given isotope, the sum of the numbers of protons and neutrons in the nucleus is called the mass number. This is because each proton and each neutron weigh one atomic mass unit.
By adding together the number of protons and neutrons and multiplying by$1amu$, we can calculate the mass of the atom.
If there are $14$ protons, then, $Z$, the atomic number is $14$. Because $Z$ is by definition the number of positively charged, massive nuclear particles.
If $Z$ is the identity of the atom and is $Z = 14$, then we have silicon. Because the element may contain more or less neutrons than $Z$, where neutrons are massive, neutrally charged, nuclear particles, the isotope is $^{28}S$.
So, the isotope which has $14$ protons and $14$ neutrons is silicon.
Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure element in the Earth's crust. More than $90\%$ of the Earth's crust is composed of silicate minerals.

Note:
Silicon could be found attached to other elements, for instance, oxygen. Silicates are the rocks which contain both silicon and oxygen. When decontaminated, it is a greyish crystal that looks metallic, although it may be glistening like metal, it is not a metal.