Chapter U1, Problem SIII2RQ

Interpretation Introduction

Interpretation:

Formation of elements in nature is to be explained.

Concept introduction:

Elements can be formed through nuclear reactions if somehow the nuclei of elements can be changed. It is very difficult to change the nucleus of a stable atom.

Answer to Problem SIII2RQ

Elements can be formed in nature through radioactive decay and through nuclear reactions like nuclear fusion in stars that exploded billions of years ago.

Explanation of Solution

There are several processes that lead to formation of elements.

• When radioactive decay occurs in some unstable isotopes, new elements are formed. For example: Uranium undergoes alpha decay and forms thorium.
• Nuclear fusion reactions in stars that exploded billions of years ago resulted in formation of some elements such as gold. There has been little change in the amounts of these elements which is due to radioactive decay and fission. Gold on Earth came from supernova explosions that might have occurred billions of years ago.

Conclusion

Elements are formed through nuclear reactions. Radioactive decay, nuclear fission and nuclear fusion are some possible ways of forming new elements.