Question

I have been reading about isotopes and their abundance on Wikipedia. It states that lithium has 2 stable isotopes, beryllium has 1 stable isotope (monoisotopic and mononuclidic) and boron has 2 stable isotopes. Although the total number of radioisotopes is much larger than the stable ones in each of these three, that is not the point of the question.

The actual question is if lithium and boron have 2 stable isotopes each, why does beryllium, which comes between lithium and boron, has only one stable isotope? What factor is making this happen here?

Answer 1

The reason beryllium, which comes between lithium and boron on the periodic table, has only one stable isotope is because of the arrangement of protons and neutrons in its nucleus.

Step-by-step explanation:

Lithium and boron both have two stable isotopes each. The reason beryllium, which comes between lithium and boron on the periodic table, has only one stable isotope is because of the arrangement of protons and neutrons in its nucleus.

Beryllium has an atomic number of 4, which means it always has 4 protons. The stable isotope of beryllium, known as beryllium-9, has a mass number of 9. This means it contains 4 protons and 5 neutrons.

Since beryllium-9 is the only stable isotope of beryllium, it means that the arrangement of 4 protons and 5 neutrons in its nucleus is more stable than any other combination of protons and neutrons.