Predict which is radioactive and which is stable

Predict the nuclear decay process for an isotope that has a too man Watch concept videos about Band of Stability. Question One of the nuclides in each of the following pairs is radioactive. Predict which is radioactive and which is stable. Submit Comment. For Potassium— The given atomic mass is 39 and the atomic number of potassium is Potassium—39 is stable For Potassium— The given atomic mass is 40 and the atomic number of potassium is Sign up to view answer.

Sign up for free to see the solution Continue with Gmail Continue with Facebook or continue watching with email "Clutch really helped me by reinforcing the things I learned in class and making exam reviews a breeze. University of Texas at Austin. Log in with Facebook. Log in with Gmail. Don't have an account? Although most of the known elements have at least one isotope whose atomic nucleus is stable indefinitely, all elements have isotopes that are unstable and disintegrate, or decay, at measurable rates by emitting radiation.

Some elements have no stable isotopes and eventually decay to other elements. In contrast to the chemical reactions that were the main focus of earlier chapters and are due to changes in the arrangements of the valence electrons of atoms, the process of nuclear decay results in changes inside an atomic nucleus. We begin our discussion of nuclear reactions by reviewing the conventions used to describe the components of the nucleus.

The protons and neutrons that make up the nucleus of an atom are called nucleons , and an atom with a particular number of protons and neutrons is called a nuclide. Nuclides with the same number of protons but different numbers of neutrons are called isotopes. Isotopes can also be represented by an alternative notation that uses the name of the element followed by the mass number, such as carbon The stable isotopes of oxygen, for example, can be represented in any of the following ways:.

For example, in a typical terrestrial sample of oxygen, Any nucleus that is unstable and decays spontaneously is said to be radioactive , emitting subatomic particles and electromagnetic radiation. The emissions are collectively called radioactivity and can be measured. Isotopes that emit radiation are called radioisotopes.

The nucleus of an atom occupies a tiny fraction of the volume of an atom and contains the number of protons and neutrons that is characteristic of a given isotope. All stable nuclei except the hydrogen-1 nucleus 1 H contain at least one neutron to overcome the electrostatic repulsion between protons. As the number of protons in the nucleus increases, the number of neutrons needed for a stable nucleus increases even more rapidly.

Too many protons or too few neutrons in the nucleus result in an imbalance between forces, which leads to nuclear instability. Several stable isotopes of light atoms have a neutron-to-proton ratio equal to 1 e.

All other stable nuclei have a higher neutron-to-proton ratio, which increases steadily to about 1. Moreover, certain numbers of neutrons or protons result in especially stable nuclei; these are the so-called magic numbers 2, 8, 20, 50, 82, and Most stable nuclei contain even numbers of both neutrons and protons.

Let me begin by pointing out that the half-life of U is about 4. If one decayed today, maybe you should buy a lottery ticket. Radioactive decay is subject to statistical and probabilistic operations, and predictions depend on large populations of nuclei.

If you have lots of atoms of U, then it is highly likely that in 4. But there is no way to predict when a particular pun intended nucleus is going to decay. A nucleus consists of protons and neutrons held together by powerful forces.