The Chart of the Nuclides is a tool that maps all known nuclides by plotting their protons vs neutrons. It displays information on stable and unstable isotopes like their symbol, mass number, decay mode, and half-life. Radioactive isotopes will decay along the chart until reaching stability, often led. The chart allows analysis of decay chains and is important in understanding nuclear processes and radiation.

1. Nuclear Radiation
Chart of the Nuclides

2. Chart of the Nuclides
 The Chart of the Nuclides is important to
understand because it is a common tool used in the
radiation industry
 The Chart is similar to the periodic table in that it
lists all known elements, atomic #’s, atomic mass,
etc.
 However, it also gives all the different known
isotopes for each element
 The Chart is in reality a graph of all the known
nuclides graphing proton # vs. neutron #

4. Chart of the Nuclides
 The row #’s are equivalent to the atomic
number of the element
 Thus each row, represents a different
element
 The column #’s are equivalent to the
neutron numbers of the nuclides

12. Chart of the Nuclides
 The first box in each row is a label for that
row, it is not a nuclide
 The information given in that box includes..
 The chemical symbol & name of the element
 The atomic mass of the element
 The absorption cross section in the units of
Barns (σ)
 A Barn is a unit of area which is determined
by the diameter of the nucleus

14. Chart of the Nuclides
 Stable nuclides are gray colored boxes, they
contain…
 The chemical symbol of the element
 The number of nucleons (Protons + Neutrons),
which equals the atomic mass
 The % of abundance in nature
 And the capture cross section in Barns (σ)
 The plot of all the stable nuclides, called the
line of stability, forms a linear plot ~ 45º

16. Chart of the Nuclides
 Unstable nuclides are indicated by all the
other boxes shown on the chart
 Each of those boxes contain…
 The chemical symbol of the element
 The number of nucleons, or atomic mass
 The half-life of the nuclide
 a – years, d – days, h – hours, m – minutes
 s – seconds, ms – milliseconds, µs – microseconds
 ~ - approximately

17. Half-Life
• Half-life, t1/2, is the time required for half the atoms of
a radioactive nuclide to decay.
• Each radioactive nuclide has its own half-life.
• More-stable nuclides decay slowly and have longer
half-lives.

18. Half-Life
Click below to watch the Visual Concept.

20. Potassium-40 Half-Life

21. Rate of
Decay

22. Half-Lives of Some Radioactive Isotopes

23. Chart of the Nuclides
 Mode of decay i.e. α - alpha, β - beta, It –
Isomeric Transition
 Energy of decay, given in MeV
 γ - gamma emission, which is a result of decay
 Gamma energies in KeV

25. Chart of the Nuclides
 Another type of nuclide shown on the chart
are those that undergo isomeric decay
 Isomeric decay results from a nuclide
giving off an alpha or beta and becoming a
metastable form
 These atoms will give off energy like a
gamma when they de-excite at a later time
 These are shown on the chart as a box
inside a box

27. Chart of the Nuclides
 Some radioactive nuclides can undergo
what is called “branching” decay
 This means that under some circumstances
they can give off one form of radiation, but
under other circumstances they give off
another
 Example – Copper 64, gives off beta – or beta +
 Both modes of decay will be given in the
box on the chart

30. Chart of the Nuclides
 Using the Chart of the Nuclides we can
easily tell what a radioactive isotope
changes into after decay
 By moving from box to box based on
whether or not protons or neutrons are lost
or gained as a result of radiation release, we
can determine the resulting isotope

37. Chart of the Nuclides
 Using this information you can follow
radioactive decay until it reaches stability
 In nature, there are three naturally occurring
decay chains
 They each begin with nuclides that have
long enough half-lives that they have been
present since the formation of the Earth

39. Chart of the Nuclides
 As the nuclides in the decay chains release
radiation, they change into other nuclides
that are also radioactive
 They continue this process until they reach
a stable isotope (usually lead)
 i.e. All of the Uranium 238 on the earth will
eventually become lead

41. Chart of the Nuclides
 There is another decay chain that was
created with the beginnings of nuclear
energy (Man Made)
 It is called “Transuranic Decay Chain” and
begins with the element Plutonium
 This leads us into the two activities which
use the Chart of the Nuclides
 Activity 1 & 2 pp 117 - 119