Nuclides - composite particles

A nuclide is a type of atom whose nuclei have specific numbers of protons and neutrons (both are called nucleons). Therefore, nuclides are composite particles of nucleons.

According to the standard model, up and down quarks are the basic components of nucleons. Thus, nuclides can also be considered composite particles of quarks

The term isotopes is often used to mean nuclides, because a nuclide is usually an isotope of an element. Strictly speaking, isotopes are atoms with the same number of protons but different number of neutrons in their nuclei.

Notation for a nuclide

The notation for a nuclide with mass number A and atomic number Z is representd by a symbol of its element E.

Notation of a nuclide

For example


In the discussion of decay families, we have used a table to show the relationship of nuclides. This type of table is very convenient for showing nuclear properties. A portion of the table for very light nuclides is given below:

# of p
2_ 3He, 0.0001%

4He, 100%


6He, 0.8 s
b, 3.51 MeV
11H, 99.99%

2H, 0.015%

3H, 12.26y
b, 0.0186 MeV
_01 2 3 4 (# of n)

A complete Table of nuclides is a large chart, and many formats have been employed on the Internet for providing this type of information. For example, The Table of Nuclides gives a complete chart, and when a region is clicked, some portion of the chart is loaded. The Map of Nuclides is divided into several sections, and you may choose a section to view.

Stable and Unstable Nuclides

There are stable and radioactive nuclides. Stable nuclides exist for an indefinite period of time, and they are the constituents of ordinary material. Unstable nuclides emit subatomic particles, with 4a, b, g, n, p being the most common. Few undergo nuclear fission. However, unstable nuclides with long half-lives are also present in nature.

Stable nuclides are not radioactive. They remain unchanged for an indefinite period.

Unstable nuclides are radioactive, and they emit alpha, beta, gamma, or proton and they eventually convert to stable nuclides.

The study of nuclides is an experimental and observatory science. It involves data gathering, classification, organization, observation, and theorization about nature.

Internet Resource

Chart of nuclides
Map of nuclides
Periodic table of elements
Table of nuclides
Exploring the table of isotopes
The pictorial periodic table
Nuclear chart for isotope explorer

Nuclear chart for isotope viewr

The Nuclear Shell Model
Stability of Isotopes

Evolution of the universe