Question

Which of the following elements shows the maximum number of stable isotopes?
A. H
B. O
C. Sn
D. S

Answer 1

To solve this question we should have knowledge of isotopes. Isotopes can be defined as species having the same atomic number and different atomic mass. Some isotopes can be radioactive and their also stability of all isotopes of an atom varies.

Complete solution:
Let us first discuss the isotopes of all these atoms and about their stabilities.
Hydrogen has three isotopes: protium $_1^1H$, deuterium $_1^2H$ and tritium $_1^3H$.These isotopes differ from one another in respect of the presence of neutrons. Hydrogen or protium has 1 proton and 0 neutrons, deuterium has 1 proton and 1 proton, tritium has 1 proton and 2 neutrons.Of these isotopes tritium is only radioactive isotope having half life of 12.33 years.
Oxygen has three isotopes: The element oxygen is found in three naturally occurring stable isotopes, $^{18}O$, $^{17}O$, $^{16}O$.These isotopes have same protons but different number of neutrons. $^{16}O$ have 8 protons and 8 neutrons, $^{17}O$ have 8 protons and 9 neutrons and $^{18}O$ have 8 protons and 10 neutrons.
And you know that among all these isotopes of oxygen $^{16}O$ is the most abundant on the earth atmosphere. Oxygen has 17 other radioactive isotopes also and each of these isotopes have half-life less than 2 minutes.
Tin has ten isotopes: Sn has 10 isotopes ranging from $Sn-112$ to $Sn-124$ except $Sn-121$ and $Sn-123$.
Sulphur has 4 stable isotopes which are $^{32}S$,$^{33}S$,$^{34}S$ and $^{36}S$.
Hence we see that Sn has the highest number of isotopes among all options.

**Therefore Correct Option is C. Sn

Note: **
An atom can have many numbers of isotopes but we have to count only stable isotopes. Also we have to read NCERT to learn all these details. You can also remember the half-life of isotopes.