Chapter U1, Problem 12RE

Interpretation Introduction

Interpretation:

The formation of one element from another element is to be explained.

Concept introduction:

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

Answer to Problem 12RE

One element can be changed to another new element by changing the number of protons in the nucleus. Processes which can bring about these changes are:

• Radioactive decay and
• Nuclear reactions like nuclear fission and fusion.

Explanation of Solution

There are several processes that can help in formation of new elements.

• When radioactive decay occurs in some unstable isotopes, new elements are formed. For example: Uranium undergoes alpha decay and forms thorium. Some unstable isotopes emit beta particles and form new elements. For example, carbon - 14 emits beta particle and forms nitrogen - 14.
• Nuclear changes occur continuously in Sun and other stars. Nuclear fusion reactions in the Sun produce helium from hydrogen atoms. Sun cannot produce elements beyond helium as it is not hot enough but other hotter stars can produce heavier elements such as iron. Some supernova explosion can even produce elements heavier than iron such as gold.
• On Earth, scientists are able to produce new elements through nuclear fission reactions in nuclear reactors. The power is generated through these controlled chain reactions. Nuclear fusion is not possible on Earth because large amount of energy is needed to fuse nuclei.

Conclusion

Elements are formed through nuclear reactions. Radioactive decay, nuclear fission and nuclear fusion are some possible ways of forming one element from other.