Why do gamma rays require the heaviest shielding

Thorium is a nucleus that undergoes beta decay. Here is the nuclear equation for this beta decay:. Frequently, gamma ray production accompanies nuclear reactions of all types.

Virtually all of the nuclear reactions in this chapter also emit gamma rays, but for simplicity the gamma rays are generally not shown.

Nuclear reactions produce a great deal more energy than chemical reactions. Nuclear reactions release some of the binding energy and may convert tiny amounts of matter into energy. That means that nuclear changes involve almost one million times more energy per atom than chemical changes! Figure Confirm that this equation is correctly balanced by adding up the reactants' and products' atomic and mass numbers.

The mass numbers of the original nucleus and the new nucleus are the same because a neutron has been lost, but a proton has been gained, and so the sum of protons plus neutrons remains the same. The atomic number in the process has been increased by one since the new nucleus has one more proton than the original nucleus. In this beta decay, a thorium nucleus has one more proton than the original nucleus.

In this beta decay, a thorium nucleus has become a protactinium nucleus. Protactinium is also a beta emitter and produces uranium Once again, the atomic number increases by one and the mass number remains the same; this confirms that the equation is correctly balanced.

When studying nuclear reactions in general, there is typically little information or concern about the chemical state of the radioactive isotopes, because the electrons from the electron cloud are not directly involved in the nuclear reaction in contrast to chemical reactions.

So it is acceptable to ignore charge in balancing nuclear reactions, and concentrate on balancing mass and atomic numbers only. This reaction is an alpha decay. We can solve this problem one of two ways:. Solution 2: Remember that the mass numbers on each side must total up to the same amount. The same is true of the atomic numbers. Emitting a beta particle causes the atomic number to increase by 1 and the mass number to not change.

We get atomic numbers and symbols for elements using our periodic table. We are left with the following reaction:. Emitting an alpha particle causes the atomic number to decrease by 2 and the mass number to decrease by 4. We are left with:. The decay of a radioactive nucleus is a move toward becoming stable.

Often, a radioactive nucleus cannot reach a stable state through a single decay. In such cases, a series of decays will occur until a stable nucleus is formed. Several of the radioactive nuclei that are found in nature are present there because they are produced in one of the radioactive decay series.

For example, there may have been radon on the earth at the time of its formation, but that original radon would have all decayed by this time.

The radon that is present now is present because it was formed in a decay series mostly by U A nuclear reaction is one that changes the structure of the nucleus of an atom. The atomic numbers and mass numbers in a nuclear equation must be balanced.

Protons and neutrons are made up of quarks. The two most common modes of natural radioactivity are alpha decay and beta decay. Most nuclear reactions emit energy in the form of gamma rays. This page was constructed from content via the following contributor s and edited topically or extensively by the LibreTexts development team to meet platform style, presentation, and quality:.

Express the changes in the atomic number and mass number of a radioactive nuclei when an alpha, beta, or gamma particle is emitted. Write nuclear equations for alpha and beta decay reactions. Beta-emitters are most hazardous when they are inhaled or swallowed. Gamma rays can pass completely through the human body; as they pass through, they can cause damage to tissue and DNA. Radioactive decay occurs in unstable atoms called radionuclides.

The energy of the radiation shown on the spectrum below increases from left to right as the frequency rises. Other agencies regulate the non-ionizing radiation that is emitted by electrical devices such as radio transmitters or cell phones See: Radiation Resources Outside of EPA. Alpha particles come from the decay of the heaviest radioactive elements, such as uranium , radium and polonium.

Even though alpha particles are very energetic, they are so heavy that they use up their energy over short distances and are unable to travel very far from the atom. The health effect from exposure to alpha particles depends greatly on how a person is exposed. Alpha particles lack the energy to penetrate even the outer layer of skin, so exposure to the outside of the body is not a major concern. Inside the body, however, they can be very harmful. If alpha-emitters are inhaled, swallowed, or get into the body through a cut, the alpha particles can damage sensitive living tissue.

The way these large, heavy particles cause damage makes them more dangerous than other types of radiation. The ionizations they cause are very close together - they can release all their energy in a few cells.

This results in more severe damage to cells and DNA. These particles are emitted by certain unstable atoms such as hydrogen-3 tritium , carbon and strontium Beta particles are more penetrating than alpha particles, but are less damaging to living tissue and DNA because the ionizations they produce are more widely spaced.

They travel farther in air than alpha particles, but can be stopped by a layer of clothing or by a thin layer of a substance such as aluminum. However, as with alpha-emitters, beta-emitters are most hazardous when they are inhaled or swallowed. Unlike alpha and beta particles, which have both energy and mass, gamma rays are pure energy. Gamma rays are similar to visible light, but have much higher energy. Gamma rays are often emitted along with alpha or beta particles during radioactive decay.

Gamma rays are a radiation hazard for the entire body. They are lighter than alpha particles, and can travel farther in air, up to several yards. Very energetic beta particles can penetrate up to one-half an inch through skin and into the body.

They can be shielded with less than an inch of material, such as plastic. In the case of lower energy beta particles, the outer layer of clothing can act as an effective shield. Gamma rays can be emitted from the nucleus of an atom during radioactive decay.

They are able to travel tens of yards or more in air and can easily penetrate the human body.