Question

Which of the following has magic number of protons and neutrons?

• A. ${{\,}_{8}}{{O}^{17}}$
• B. ${{\,}_{13}}A{{l}^{27}}$
• C. ${{\,}_{9}}{{F}^{17}}$
• D. ${{\,}_{20}}C{{a}^{40}}$

Answer 1

Answer: (D)

${{\,}_{20}}C{{a}^{40}}$

Answer 2

Nuclei such as $_{2}H{{e}^{4}},{{\,}_{8}}{{O}^{16}},{{\,}_{20}}C{{a}^{40}}$ and $_{\,82}P{{b}^{208}}$ which contains protons equal to 2, 8, 20 and 82 respectively (all magic numbers) and neutrons equal to 2, 8, 20 and 126 respectively (also magic numbers) are most stable. Note: Nuclei with 2, 8, 20, 28, 50, 82 or 126 protons or neutrons have been found to be stable with a large no. of isotopes. These number are known as magic numbers.