Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 21: Problem 78

Identify two of the most abundant radioactive elements that exist on Earth. Explain why they are still present. (You may need to consult a handbook of chemistry.)

Short Answer

Expert verified
The two most abundant radioactive elements on Earth are Uranium and Thorium. They are still present due to their long half-lives (4.5 billion years for Uranium-238 and 14 billion years for Thorium-232), which means they decay very slowly. The replenishment from processes like cosmic ray spallation and Earth's internal heat also contributes to their sustained presence.

Step by step solution

01

Identify the Most Abundant Radioactive Elements

The two most abundant radioactive elements on Earth are uranium (U) and thorium (Th). These elements are found in small amounts in the Earth's crust.
02

Understand the Concept of Half-Life

The half-life of a radioactive element is the time it takes for half of the atoms in a sample of that element to decay. It is a measure of how long the element will persist. Uranium-238, for example, has a half-life of about 4.5 billion years, and Thorium-232 has a half-life of about 14 billion years.
03

Explain Why Uranium and Thorium Are Still Present

Given their long half-lives, substantial amounts of uranium and thorium still remain, even though they were formed when Earth itself was formed. The long half-lives of these elements allow them to still exist in significant amounts, despite being in a constant state of decay. Moreover, these elements are continually replenished through the process of cosmic ray spallation, and also from the Earth's internal heat, from elements such as Potassium-40.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

The radioactive decay of \(\mathrm{T} 1-206\) to \(\mathrm{Pb}-206\) has a half- life of 4.20 min. Starting with \(5.00 \times 10^{22}\) atoms of \(\mathrm{Tl}-206,\) calculate the number of such atoms left after 42.0 min.

A radioactive substance undergoes decay as: $$ \begin{array}{cc} \text { Time (days) } & \text { Mass (g) } \\ \hline 0 & 500 \\ 1 & 389 \\ 2 & 303 \\ 3 & 236 \\ 4 & 184 \\ 5 & 143 \\ 6 & 112 \end{array} $$ Calculate the first-order decay constant and the halflife of the reaction.

What is the belt of stability?

For each pair of elements listed, predict which one has more stable isotopes: (a) Co or \(\mathrm{Ni},\) (b) \(\mathrm{F}\) or \(\mathrm{Se}\) (c) Ag or Cd.

Write balanced nuclear equations for these reactions and identify \(\mathrm{X}:\) (a) \(\mathrm{X}(\mathrm{p}, \alpha){ }_{6}^{12} \mathrm{C},\) (b) \({ }_{13}^{27} \mathrm{Al}(\mathrm{d}, \alpha) \mathrm{X}\) (c) \({ }_{25}^{55} \mathrm{Mn}(\mathrm{n}, \gamma) \mathrm{X}\)
See all solutions

Recommended explanations on Chemistry Textbooks

Ionic and Molecular Compounds

Read Explanation

The Earths Atmosphere

Read Explanation

Chemical Analysis

Read Explanation

Making Measurements

Read Explanation

Organic Chemistry

Read Explanation

Inorganic Chemistry

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free