Which pair of atoms is an example of isotopes?
An atom with 11 protons and 12 neutrons, and one with 11 protons and 13 neutrons.
Isotopes are atoms of the same element, so they have the same number of protons (the same atomic number), but they have different numbers of neutrons and therefore different mass numbers.
Atoms with 11 protons and 12 neutrons, and with 11 protons and 13 neutrons, both have atomic number 11, so both are sodium, but their mass numbers are 23 and 24. So this pair is an example of isotopes.
The pair with 12 and 11 protons are different elements with the same mass number 24, so they are isobars, not isotopes. The pair with 11 protons and 12 neutrons twice are identical atoms. The pair with 11 and 12 protons are different elements, so they cannot be isotopes either.
Hence, An atom with 11 protons and 12 neutrons, and one with 11 protons and 13 neutrons.
Similar Questions
Consider the following statements regarding Thomson's model of an atom.
Statement I: The atom is a sphere of positive charge with electrons scattered inside it.
Statement II: Thomson's model could explain the presence of the nucleus in an atom.
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A species having 8 electrons in the third shell is very reactive while the other species having 8 electrons in the third shell is very inactive they are :
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