Chapter U1.16, Problem 3E

Interpretation Introduction

Interpretation: Nuclear equation for beta decay of cerium - 141 is to be written.

Concept introduction: Unstable elements can be changed to new elements by emitting subatomic particles. When electrons are emitted from nucleus of an atom, it is called beta decay. The emitted electron is called beta particle.

Answer to Problem 3E

The nuclear equation for beta decay of cerium - 141 can be written as:

${}_{58}^{141}\text{Ce}{\to }_{59}^{141}\mathrm{Pr}+\beta$

Explanation of Solution

Given information :

A beta particle is emitted from cerium - 141.

Explanation :

During beta decay, a neutron splits into a proton and an electron. So the number of protons increase by one and number of neutrons decrease by one in the nucleus. The mass number however remains the same as sum of number of protons and neutrons is same, but the atomic number increases by one. Beta particle is same as an electron.

When an atom of cerium - 141 undergoes beta decay, an atom of new element is produced and a beta particle is produced. New element has 1 proton more than cerium. From the periodic table one can find out the atomic number of cerium that is58.

So, atomic number of new element will be 58 + 1=59

The mass number of new and cerium will be same that is 141.

From the periodic table, new element with atomic number 59 is praseodymium (Pr).

The nuclear equation for beta decay can be written as:

${}_{58}^{141}\text{Ce}{\to }_{59}^{141}\mathrm{Pr}+\beta$

Conclusion

Beta decay of cerium - 141 results in formation of praseodymium - 141 and an electron (beta particle).