Chapter 25, Problem 72A

Interpretation Introduction

Interpretation:

Elements represented by the following symbols and indicate which of them would have no stable isotopes.

Concept introduction:

The majority of elements can be found in two or more isotopes. Isotopes differ in mass because they have the same amount of protons but differing numbers of neutrons.

Answer to Problem 72A

(b) Thorium has no stable isotopes.

(c) Francium has no stable isotopes.

(f) Californium has no stable isotopes.

Explanation of Solution

We know that all elements with atomic numbers above 83 are unstable because they have too many neutrons and protons for them to be stable and they are known as radioactive elements. The atomic numbers of thorium, Francium, and Californium are 82, 87, and 98 respectively. So, all there are radioactive and have no stable isotopes.

Conclusion

Reason for incorrect options (a) Pt has stable isotopes.

(e) Xenon will have stable isotopes.

(d) Titanium has stable isotopes.

Since platinum has the atomic number $78$ , we can conclude that this element has stable isotopes because its atomic number is below $83$ .

Xenon is a noble gas and are stable.

Atomic number of titanium is 22, so it has stable istope.