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These atoms are isotopes
Isotopes are atoms with the same number of protons (which determine the atomic number) and a different number of neutrons. These two atoms have the same number of protons (13), but a different number of neutrons, so they are isotopes.
According to their number of protons, these are Aluminum isotopes: ²⁷Al (stable), and ²⁶Al (radioactive), respectively.
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I think the answer should be the last one. Magnets attract magnets with unlike poles and repel magnets with like poles
Density of copper: 8,9
Density of steel: 7,7
Density of aluminum: 2,7
And
Resistivity of copper: 1,7
Resistivity of steel: 16,9
Resistivity of aluminum: <span>2,7</span>
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