Physics Nuclear Revision


Atomic Structure

An atom is made from a nucleus surrounded by electrons which contan protons and neutrons

The Mass Number is the top number-The Atomic Number is the bottom number

An ISOTOPE is an atom that have the same number protons but different number of protons

The plum pudding model was the first model of an atomdiscovered by Rutherfood

  • Isotopes
  • The number of electrons in an atom is always the same as the number of protons so the atom is neutral
  • The total number of protons and neutrons in an atom is its mass number
  • Charged particles called ions are formed when atoms loose or gain electrons
    • if an atom looses one or more electrons it becomes positively charged
    • if an atom gains one or more electrons it becomes negitively charged
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Radioactive Decay

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Radioactive Decay

  • When Isotopes are unstable they can decay or split wich emitts radiation
  • Called a Radioactive Isotope
  • When a radioactive isotope decays, it forms a different atom with a different number of protons
  • When an atom emits alpha or beta radiation, its nucleus changes
  • It becomes the nucleus of a different element
  • This is because the number of protons in the nucleus changes which element the atom belongs to
    • Alpha Decay - The nucleus looses 2 protons and 2 neutrons and 2 neutrons and are emitted as an alpha particle
    • Beta Decay - A neutron in the nucleus changes into a proton and an electron is created in the nucleus and instantly emitted
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