Distinguish Between Stable and Radioactive Isotopes and Describe the Conditions under Which a Nucleus Is Unstable

Isotopes refer to an element that has different numbers of neutrons, but the same number of protons and electrons. Isotopes of the same element differ in the mass number but not the atomic number

Mass number – number of nucleons (protons and neutrons)

Carbon-13 is an isotope, as it has 6 protons and 7 neutrons.

A stable isotope does not go through radioactive decay. This is because the neutrons and protons are in such a low energy level that they are unable to release energy.

For each isotope there is a favoured balance of neutrons and protons so that they are held together well. If an atom has too many neutrons its starts to decay. The kinds of radiation emitted are alpha, beta and gamma particles.

Radioactive decay refers to unstable isotopes constantly emitting energy (or radiation).

-A stable isotope does not release radiation, but a radioactive isotope does.

- A radioactive isotope releases radiation. Radiation comes in 3 forms: Alpha     Beta       gamma

|Name                 |Symbols               |Identity                 |Relative Mass         |Relative Charge       |Penetrating power         |
|                     |                     |                         |Hydrogen = 1           |                     |                         |
|Alpha                 |a                     |Helium Nucleus           |4                     |+2                   |Low           (thin sheet|
|                     |                     |                         |                       |                     |of paper)                 |
|beta                 |b                     |Electron                 |1/1836                 |-1                   |Medium     (0.5 mm of     |
|                     |                     |                         |                       |                     |lead)                     |
|gamma                 |y...