Chapter U1.16, Problem 1E

Interpretation Introduction

Interpretation: Four processes that lead to the formation of new elements are to be described.

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 1E

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:

1. Radioactivealpha decay
2. Beta decay
3. Nuclear fission
4. Nuclear fusion.

Explanation of Solution

Given information:

New elements can be formed from old elements by four processes.

Explanation:

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

1. Radioactive alpha decay - When radioactive decay occurs in some unstable isotopes, new elements are formed by emitting alpha particles. For example: Uranium undergoes alpha decay and forms thorium.
2. Beta decay - Some unstable isotopes emit beta particles and form new elements. For example: carbon - 14 emits beta particle and forms nitrogen - 14.
3. Nuclear fission - When nucleus of an atom splits to form two atoms with smaller nuclei, the process is called fission. Scientists conduct nuclear fission reactions by bombardment of neutrons to a nucleus. Scientists are able to produce new elements through nuclear fission reactions in nuclear reactors. The power is generated through these controlled chain reactions. For example, uranium can undergo fission by bombarding it with neutrons. This produces other smaller isotopes and more neutrons which can further react with other uranium atoms. This results in chain reactions producing large amounts of energy.
4. Nuclear fusion - Nuclear fusion reactions in the Sun produce helium from hydrogen. Sun cannot produce elements beyond helium as it is not hot enough but other hotter stars can produce heavier elements such as iron. Some explosion can even produce elements heavier than iron such as gold.

Nuclear fusion is not possible naturally on Earth because large amount of energy is needed.

Conclusion

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