Question

Which of the following pair(s) is/are isodiaphers?

• A. ${}_6^{14}Cand{}_{11}^{23}Na$
• B. ${}_{12}^{24}Mgand{}_{11}^{23}Na$
• C. ${}_2^{4}Heand{}_8^{15}O$
• D. ${}_9^{19}Fand{}_6^{13}C$

Answer 1

The correct option is D ${}_9^{19}Fand{}_6^{13}C$

Isodiaphers are species with different atomic numbers and mass numbers, but with the same number of neutrons in excess.
${}_9^{19}Fand{}_6^{13}C$ have different atomic numbers and different mass numbers.
Calculating the difference (n – p),
Number of neutrons (n) in ${}_9^{19}F$= 19 – 9 = 10, number of protons (p) = 9 So,
n – p = 1
Number of neutrons (n) in ${}_6^{13}C$ = 13 – 6 = 7, number of protons (p) = 6. So,
n – p = 1