Skip to main content
Ch.20 - Nuclear Chemistry
Chapter 20, Problem 40

Of the two isotopes of tungsten, 160W and 185W, one decays by b emission and one decays by a emission. Which does which? Explain.

Verified step by step guidance
1
insert step 1> Determine the type of decay each isotope undergoes by considering the stability of the isotopes.
insert step 2> Understand that beta (β) emission typically occurs in isotopes with a high neutron-to-proton ratio, as it converts a neutron into a proton.
insert step 3> Recognize that alpha (α) emission usually occurs in heavy isotopes with a high atomic mass, as it helps the nucleus lose mass and become more stable.
insert step 4> Compare the neutron-to-proton ratios of 160W and 185W to determine which isotope is more likely to undergo beta decay.
insert step 5> Conclude that the isotope with the higher neutron-to-proton ratio will undergo beta decay, while the heavier isotope will undergo alpha decay.

Verified Solution

Video duration:
2m
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Isotopes

Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons. This difference in neutron count results in varying atomic masses and can influence the stability of the nucleus. For tungsten, the isotopes 160W and 185W represent two different atomic masses, which can affect their decay processes.
Recommended video:

Alpha and Beta Decay

Alpha decay involves the emission of an alpha particle, which consists of two protons and two neutrons, leading to a decrease in atomic number by two and mass number by four. In contrast, beta decay occurs when a neutron is transformed into a proton, emitting a beta particle (an electron) and increasing the atomic number by one. The type of decay is influenced by the stability of the isotopes.
Recommended video:

Nuclear Stability

Nuclear stability is determined by the ratio of neutrons to protons in an atomic nucleus. Isotopes with an optimal ratio tend to be stable, while those with too many or too few neutrons may undergo radioactive decay to achieve stability. The specific decay mode (alpha or beta) is influenced by this stability, with heavier isotopes often favoring alpha decay and lighter or neutron-rich isotopes favoring beta decay.
Recommended video:
Guided course
03:29
Band of Stability: Nuclear Fission