Key Stage 4
Meaning
Unstable Isotopes are isotopes which radioactively decay to form new stable isotopes of the same element or a different element.
About Unstable Isotopes
- An isotope may be unstable if:
- It has too many neutrons
- It has too few neutrons
- The nucleus is too massive.
- It has excess vibrational energy.
- An unstable isotope may decay causing it to transmute into a new element or a more stable isotope of the same element by releasing a particle from the nucleus.
- An unstable isotope may be too massive so it can lose an alpha particle to become a less massive element or it can split into two smaller, more stable elements in a process called nuclear fission.
- An unstable isotope may be vibrating with excess energy so to lose this energy it will emit gamma radiation.
This is a key to show the types of particles in the following decays of unstable nuclei. | This nucleus is unstable because it has too many neutrons relative to protons so it decays via neutron radiation reducing the atomic mass by 1. |
This nucleus is unstable because it is too massive and has too few neutrons relative to protons so it decays via alpha emission reducing the atomic mass by 4 and the atomic number by 2. | This nucleus is unstable because it is too many neutrons so it decays via beta emission in which a neutron turns into a proton increasing the atomic number by 1. |
This nucleus is unstable because it is has excess vibrational energy so it decays by emitting a gamma ray. After the decay it still has the same atomic mass and atomic number but is no longer vibrating. | This nucleus is unstable because it is far too massive and has too many neutrons so it decays by splitting into two smaller, more stable elements and releases some neutrons. |