Inside the atom

Inside the atom

1. Specific Charge

   • specific charge = charge/mass
   • unit = coulombs per kilogram (Ckg^-1)

2. Isotopes

   • Atoms of an element with the normal number of protons and electrons, but different numbers of neutrons
   • Isotopes have the same atomic number, but different mass numbers
   • The different isotopes of an element have identical chemical properties. However, some isotopes are radioactive
   • Medical Uses
     • Radiotherapy
     • Sterilisation of equipment

3. Isotopic Data

   • The relative amounts of the different isotopes of an element present in a substance is known as isotopic data

4. Decay Chains

   • Refers to a series of radioactive decays of different radioactive decay products as a sequential series of transformations
   • Also known as radioactive cascade
   • Most radioistotopes do not decay directly into a stable state. but rather undergo a series of decays until eventually a stable isotope is reached
   • Information scientists can use these decay chains to infer the age of undated nuclear materials

5. Radioactive Dating

   • Also known as radiometric dating, it is any methof of determining the age of earth materials or objects of organic origin based on measurements of either short-lived radioactive elements or the amount of a long-lived radioactive element plus its decay product
   • Helpful for figuring out the age of ancient things
   • Method
     • 1) Carbon-14 (C-14), a radioactive isotope of carbon, is produced in the upper atmosphere by cosmic radiation
     • 2) The primary carbon-containing compound in the atmosphere is carbon dioxide, and a very small amount of carbon dioxide contains C-14. Plants absorb C-14 during photosynthesis, so C-14 is incorporated into the cellular structure of plants
     • 3) Plants are then eaten by animals, making C-14 a part of the cellular structure of all living things
     • 4) As long as an organism is alive, the amount of C-14 in its cellular structure remains constant
     • 5) But when the organism dies, the amount of C-14 begins to decrease.
     • 6) Scientists know the half-life of C-14 (5,730 years ), so they can figure out how long ago the organism died

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