Several dozen radioisotopes have been characterized. 65Zn, which has a half-life of 243.66 days, is the most long-lived radioisotope, followed by 72Zn with a half-life of 46.5 hours. Zinc has 10 nuclear isomers. 69mZn has the longest half-life, 13.76 h. The superscript m indicates a metastable isotope. The nucleus of a metastable isotope is in an excited state and will return to the ground state by emitting a photon in the form of a gamma ray. 61Zn has three excited states and 73Zn has two. The isotopes 65Zn, 71Zn, 77Zn and 78Zn each have only one excited state. COUNT 10
QSN1 How many radioisotopes of zinc have been discovered? ANS1 Several dozen QSN2 What is the longest half life of the isotopes? ANS2 243.66 QSN3 What does the superscript m represent? ANS3 metastable isotope QSN4 How many excited states does 61Zn have?  ANS4 three QSN5 How many excited states does 73Zn have? ANS5 two QSN6 What is the most long lived radio isotope? ANS6 65Zn QSN7 What is the half life of 72Zn? ANS7 46.5 hours QSN8 How many nuclear isomers does zinc have? ANS8 10 QSN9 What does the superscript "m" indicate? ANS9 metastable isotope QSN10 What does a metastable isotope do to return to ground state from an excited state? ANS10 emitting a photon in the form of a gamma ray