No, the number of neutrons in an element is not necessarily equal to the number of protons in that element. The number of protons in an atom determines its atomic number and uniquely identifies the element. This number is also referred to as the proton number.
On the other hand, the total number of protons and neutrons in an atom is its mass number. The mass number represents the sum of protons and neutrons in the nucleus of an atom. While the number of protons defines the element, the number of neutrons can vary within the same element, resulting in different isotopes.
Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons. Isotopes of an element have nearly identical chemical properties but may exhibit differences in their physical properties and stability. The isotopes of an element are denoted by writing the element's symbol followed by the mass number as a superscript. For example, carbon-12 and carbon-14 are two isotopes of carbon with 6 protons but 6 and 8 neutrons, respectively.
The presence of different isotopes is what allows elements to have varying atomic masses, as the number of neutrons contributes to the total mass of an atom.