Which of the Following Are a Pair of Isotopes?
A) ${ }_{18}^{40} \mathrm{Ar}$

question 31

Multiple Choice

Which of the following are a pair of isotopes?

• A) \({ }_{18}^{40} \mathrm{Ar}\) and \({ }_{19}^{40} \mathrm{K}\)
• B) \({ }_{20}^{40} \mathrm{Ca}\) and \({ }_{19}^{40} \mathrm{K}\)
• C) \({ }_{18}^{40} \mathrm{Ar}\) and \({ }_{36}^{80} \mathrm{Kr}\)
• D) \({ }_{20}^{40} \mathrm{Ca}\) and \({ }_{19}^{39} \mathrm{~K}\)
• E) \({ }_{20}^{40} \mathrm{Ca}\) and \({ }_{20}^{42} \mathrm{Ca}\)

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