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My career - the IRE

Comment: notions of nuclear physics
• Proton : is an elementary particle (!!! Compound).
Electrically, a proton has a “positive” charge.
• Electron : is an elementary particle. Electrically, an
electron has a “negative” charge.

• Neutron : is an elementary particle. Electrically, a
neutron has a “neutral” charge.
• Nucleus : is composed of protons and neutrons also
called nucleons.
• Atom : is composed of a nucleus and electrons that
revolve around it. It is electrically neutral: the
number of protons (+) in the nucleus is equal
to the number of electrons (-) which gravitate
around it.
• Ion : if the atom loses either a proton or an
electron, the electrical balance no longer

being assured, it becomes an ion (ionization: a
charged atom, either positively - loss of an electron, or
negatively - loss of a proton).
• Isotope : has the same number of protons as the stable
element, but the number of neutrons (in the
nucleus) is different.
• Chemistry is the field of electrons which, with the bonds
between atoms (covalence’s, ions, etc.), form molecules.
• Nuclear physics is the field of the nucleus.
• For the 92 stable elements, the composition of the

nucleus never “naturally” changes.
• An element is determined by the composition of its
nucleus according to the number of protons.
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