Topic 5.1 - The Nuclear Atom Flashcards Preview

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Flashcards in Topic 5.1 - The Nuclear Atom Deck (12)
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Describe the structure of a nucleus.

The nucleus is positively charged and is made of protons (positive) and neutrons (neutral).


What are the relative charges of protons, electrons and neutrons?

  • Protons: +1
  • Electrons: -1 
  • Neutrons: 0 


What are the relative masses of protons, electrons and neutrons?

  • Protons: 1
  • Electrons: 0 (0.0005
  • Neutrons: 1


What are the conclusions of Rutherford’s experiment?

  • Most of an atom is empty space
  • The nucleus has a positive charge  
  • Most of the mass is concentrated in the nucleus


Describe Rutherford's atomic model 

There is a positive nucleus at the centre of an atom, with negative electrons existing in a 'cloud'/region around the nucleus 


What is an isotope?

Atoms that are the same element with the same number of protons. However they have a different number of neutrons so therefore different masses.


What do all atoms of the same element share?

The same number of protons (atomic number).


What is nuclear fission?

When a large and unstable nucleus splits to form two smaller nuclei, neutrons and energy.


What is nuclear fusion?

When two small nuclei fuse to form a heavier nucleus and release energy.


What does Z represent?

The atomic (proton) number; the number of protons in the nucleus of an atom 


What does A represent?

  • The nucleon number; the numbers of protons and neutrons in the nucleus of an atom.
  • This is also known as the atom’s mass.


Describe Rutherford's experiment 

  • Alpha particles (charge +2) were fired at a thin
    sheet of gold foil
  •  Most particles went straight through
  •  Some particles were deflected by small angles
    (< 90o)
  •  A few particles were deflected by large angles
    (> 90o)