Animated Solution for Chemistry - s and p-Block Elements: The number of neutrons and electrons, respectively, present in the radioactive isotope of hydrogen is

Hydrogen is the simplest element in the universe, but it holds a few fascinating secrets. It exists in three distinct isotopic forms: Protium, Deuterium, and Tritium.

While Protium and Deuterium are stable, Tritium is the rebel of the family. It is the only radioactive isotope of hydrogen.

Imagine an atom that has packed too many neutral particles into its tiny nucleus, making it unstable and prone to radioactive decay. That is Tritium for you!

To understand the subatomic makeup of Tritium, we first need to look at its symbol: ${}_1^3\text{T}$.

The subscript $1$ represents the Atomic Number ($Z$). For any neutral atom, the atomic number tells us exactly how many protons are in the nucleus, and consequently, how many electrons are orbiting it.

The superscript $3$ represents the Atomic Mass ($A$). The atomic mass is the total heavy machinery of the atom—the sum of its protons and neutrons.

Let us start with the easiest part: the electrons.

Since Tritium is a neutral atom, the number of electrons ($n_e$) is perfectly balanced by the number of protons ($n_p$).

Because the atomic number $Z=1$, we immediately know that:

So, Tritium has exactly one electron dancing around its nucleus.

Now, let us dive into the nucleus to find the neutrons.

We know the total atomic mass is $3$. This mass is made up of protons and neutrons combined.

Since we already established there is $1$ proton, the remaining mass must come entirely from the neutrons ($n_n$).

Mathematically, we set up the equation:

Substituting our known values:

Solving for $n_n$, we get:

Tritium has exactly two neutrons packed alongside its single proton.

We have successfully mapped out the subatomic structure of Tritium.

It contains two neutrons and one electron.

This unique $2:1$ neutron-to-proton ratio is exactly what makes Tritium unstable and radioactive, unlike its lighter siblings Protium (zero neutrons) and Deuterium (one neutron).