Question

What does $X$ represent in the following symbol: ${}_{35}^{80}X$ ?

Answer 1

To know the Substitution or the exact element instead of $X$ , first we should know the isotope notations uses the given symbols. We have to know that for which particular term, 80 is substituted as well as 35 is substituted.

Complete step by step solution:
For ${}_{35}^{80}X$ , recall that the isotope notation uses the following symbols:
${}_Z^A{X^{ \pm n}}$
$\bullet$ $Z$ is the atomic number, which tells you the number of protons in the element and also its identity.
$\bullet$ $A$ is the mass number, which tells you the number of protons plus the number of neutrons.
$\bullet$ $X$ is the chemical symbol of the element, and it must correspond to the atomic number.
$\bullet$ $\pm n$ is the signed charge.
Isotope notation, also known as nuclear notation, is important because it allows us to use a visual symbol to easily determine an isotope's mass number, atomic number, and to determine the number of neutrons and protons in the nucleus without having to use a lot of words.

Note:
Now, a question arises here: can isotopes have different numbers of neutrons? However, because different isotopes have different numbers of neutrons, they can differ in mass number, which is the sum of the protons and neutrons in the nucleus.