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Structure of the Atom

The atom is made of a positively charged nucleus made of protons and neutrons.The nucleus is surrounded by electrons.It contains most of the mass of the atom.The diameter of the nucleus is 0.0001 times the diameter of the atomA nucleon is a neutron or proton.Charge:
proton+1.6 × 10-19C
electron-1.6 × 10-19C
neutron0 C
Mass:
neutron1.67 × 10-27kg
proton1.67 × 10-27kg
electron9.11 × 10-31 kg

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Specification: AQA Physics (7407), AS-level, 3.2.1.1 Constituents of the atom. Topic: Particles and Radiation.

Key terms in this lesson

Photon
A discrete packet, or quantum, of electromagnetic energy.
Antiparticle
A particle with the same rest mass as its corresponding particle but with opposite charge and opposite values of other quantum properties.
Muon
A negatively charged lepton, similar to but much heavier than the electron, produced for example by cosmic rays in the atmosphere.
Pion
A meson, made of a quark-antiquark pair, that may be positively charged, negatively charged or neutral; produced through the strong interaction and decaying through the weak interaction.
Kaon
A strange meson, produced through the strong interaction and decaying through the weak interaction, with a rest mass between that of a pion and a proton.

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