An element with atomic mass z has two isotopes having atomic masses (z-1) and (z+2). Find out the percentage abundance of heavier isotope.

Q. There are two isotopes of an element with atomic mass $z$. Heavier one has atomic mass $z+2$ and lighter one has $z-1$, then an abundance of lighter one is:

Q. Atomic mass of boron is 10.81. It has two isotopes with 80% and 20% abundance respectively. The atomic mass of the isotope having 80% abundance is 11.01. The atomic mass of the other isotope is:

Q. An element has two isotopes with atomic masses $(A-1)$ and $(A+3)$ respectively. The average atomic mass is $A$. Calculate the mole percentage of the heavier isotope.

Q. An element Z contains two naturally occurring isotopes ³⁵Z₁₇ and ³⁷Z₁₇. If the average atomic mass of this element be 35.5 u, calculate the percentage of two isotopes.

Q. (a) What are radioactive isotopes? Give two examples of radioactive isotopes.
(b) Give any two uses of radioactive isotopes.
(c) An element Z contains two naturally occurring isotopes ${}_{17}{}^{35}\mathrm{Z}$ and ${}_{17}{}^{37}\mathrm{Z}$. If the average atomic mass of this element be 35.5 u, calculate the percentage of two isotopes.