Tip 1: What is plutonium?
Tip 1: What is plutonium?
Plutonium is radioactive, silvery,metallic, transuranic chemical element. It is designated by the symbol Pu, and its atomic number is 94. The chemical element was discovered in 1940 and named after the planet Pluto.
Main characteristics of plutonium
There are 15 known isotopes of plutonium. The most important of these is Pu-239 with a half-life of 24360 years. The specific mass of plutonium is 19.84 at a temperature of 25 ° C. The metal begins to melt at a temperature of 641 ° C, boils at 3232 ° C. Its valence is 3, 4, 5 or 6. The metal has a silver hue, and it turns yellow when exposed to oxygen. Plutonium is a chemical reactive metal and is readily soluble in concentrated hydrochloric acid, in perchloric acid, in iodide hydrochloric acid. In alpha decay, the metal releases heat energy. Plutonium is the second transuranic actinide discovered by the second. In nature, this metal can be found in small quantities in uranium ores.Interesting facts about plutonium
Plutonium is toxic and requires careful handling. The most fissile isotope of plutonium was used as a reactor in nuclear weapons. In particular, it was used in a bomb that was dropped on the Japanese city of Nagasaki. It is a radioactive poison that accumulates in the bone marrow. In carrying out experiments on people in order to study plutonium, several accidents occurred, some with a fatal outcome. It is important that plutonium does not reach critical mass. In aqueous solution, plutonium forms a critical mass faster than in the solid state. The atomic number 94 means that all plutonium atoms have 94 protons. In air, plutonium oxide forms on the surface of the metal. This oxide is pyrophoric, so smoldering plutonium will flicker like ash. There are six allotropic forms of plutonium. The seventh form appears at high temperatures. In aqueous solution, plutonium changes color. On the surface of the metal appear different shades as it oxidizes. The oxidation process is unstable, and the color of plutonium can change suddenly. Unlike most substances, plutonium thickens when melted. In the molten state, this element is more viscous than other metals. Metal is used in radioactive isotopes in thermoelectric generators on which spacecraft operate. In medicine, it is used in the manufacture of electronic stimulants for the heart. Inhalation of plutonium vapors is hazardous to health. In some cases, it can provoke lung cancer. The inhaled plutonium has a metallic taste.Tip 2: What is the valence
Valence - one of the main terms used intheory of chemical structure. This concept determines the ability of an atom to form chemical bonds and quantitatively represents the number of links in which it participates.
Instructions
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Valence (from the Latin. valentia - "power") is an indicator of the ability of an atom to attach to itself other atoms, forming with them chemical bonds within a molecule. The total number of bonds in which an atom can participate is equal to the number of its unpaired electrons. Such bonds are called covalent bonds.
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Unpaired electrons are free electronsouter shell of the atom, which are conjoined with external electrons of another atom. Each such pair is called electron, and such electrons are valence. Proceeding from this, the definition of valence may sound like this: this is the number of electron pairs over which a given atom is bound to other atoms.
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Valence atom is schematically depicted in structural chemical formulas. If such information is not needed, then the simplest formulas are used, in which valence is not indicated.
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The maximum valence of chemicalelements of one group of the periodic system, as a rule, is equal to the ordinal number of the group. In different chemical compounds, the atoms of one element can have different valences. The polarity of the resulting covalent bonds is not taken into account, so the valence has no sign. It can not be either zero or negative.
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The quantitative measure of any chemical elementit is customary to consider the number of monovalent hydrogen atoms or divalent oxygen atoms. However, in the determination of valence, other elements whose valency is well known can also be used.
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Sometimes the concept of valence is identified withthe term "degree of oxidation", but this is not true, although in some cases these indicators are the same. The degree of oxidation is a formal term, meaning a possible charge that an atom would receive if its electrons in electron pairs were transferred to more electronegative atoms. In this case, the degree of oxidation is expressed in units of charge and may have a sign, in contrast to valence. This term has become widespread in inorganic chemistry, since it is difficult to judge valency in inorganic compounds. Valence It is also used in organic chemistry, since most organic compounds have a molecular structure.
Tip 3: What is alpha decay?
The phenomenon of radioactivity was discovered in 1896A. Becquerel. It consists in the spontaneous emission of radioactive radiation by certain chemical elements. This radiation consists of alpha particles, beta particles and gamma quanta.
Experiments with radioactive elements
The complex composition of radioactive radiation waswas detected by a simple experiment. A uranium sample was placed in a lead box with a small hole. Opposite the hole put a magnet. It was recorded that the radiation was "divided" into 2 parts. One of them deviated towards the north pole, and the other - towards the south pole. The first was called alpha radiation, and the second was called beta radiation. At the time, they did not know that there was a third type, gamma quanta. They do not react to the magnetic field.Alpha decay
Alpha decay is the emission of a certain nucleuschemical element of a positively charged helium nucleus. The displacement law works, and it turns into another element with a different charge and mass number. The charge number decreases by 2, and the mass number by 4. The helium nuclei that emerge from the nucleus during decay are called alpha particles. For the first time they were discovered by Ernest Rutherford in their experiments. He also discovered the possibility of transforming certain elements into others. This discovery was a turning point in all nuclear physics. Alpha decay is characteristic for chemical elements that have at least 60 protons. In this case, the radioactive transformation of the nucleus will be energetically favorable. The average energy released during alpha decay lies in the range from 2 to 9 MeV. Almost 98% of this energy carries with it the core of helium, the rest is accounted for by the recoil of the mother nucleus during decay. The half-life of the alpha emitters takes on different values: from 0.00000005 sec to 8000000000 years. Such a large spread is explained by the potential barrier that exists inside the nucleus. He does not allow the particle to fly out of it, even if it is energetically profitable. According to the ideas of classical physics, the alpha particle can not overcome the potential barrier at all, since its kinetic energy is very small. Quantum mechanics introduced its corrections to the theory of alpha decay. With some probability, the particle can still penetrate the barrier, despite the lack of energy. This effect is called tunneling. The transparency coefficient determining the probability of the particle passing through the barrier was introduced. A large spread of the half-life of alpha-emitting nuclei is explained by the different height of the potential barrier (i.e., the energy for overcoming it). The higher the barrier, the longer the half-life.Tip 4: What is a lethal weapon?
The main task of weapons in the modern world isprotection and safety of life. Unfortunately, not every weapon is intended for peaceful solutions. In the world, the most part is precisely lethal weapons.
The media regularly notifies us about lethal weapons, without giving us a clear idea of what it is. This is especially sharply discussed in the light of recent military events.
Accurately classify weapons into lethal andnon-lethal is not always possible. Even simple electric shock can cause such harm to human health, which will be incompatible with life. However, it is the weapons for self-defense that are most easily identified, since their design is intended only for partial defeat.
With mortal guns, things are a little more complicated. There is no single classification that could classify this or that type of weapon as deadly. Therefore, 100% state that the weapon is destined for destruction, it is possible only if its main task is to defeat a large territory or a large number of people.
If non-lethal weapons are used most often inlaw-enforcement spheres, then lethal has spread in the military field. This includes, first of all, various missile installations, weapons of mass destruction, firearms and even nuclear weapons. The range of applications and varieties is really very large.
Often non-lethal weapons can becomeIf you change the design, than many criminals use. However, one must know that criminal responsibility is provided for this. Remember that people are killed not by weapons, but by other people.
Tip 5: What is alpha radiation?
Radiation is a natural property of any substance,whether it's water, land or even a human body. Each item contains a certain amount of radionuclides. Alpha-, beta- and gamma-particles are types of ionizing radiation, which have a negative effect on living organisms. However, scientists have put them in the service of man, having learned with their help to treat cancerous tumors and many less dangerous diseases. Alpha particles for these purposes are used with great caution, since they have very high biological activity.
So, what is alpha radiation? This is ionizing radiation caused by the decay of radioactive isotopes. They emit fast-moving positively charged alpha particles that have a small penetrating power, so it is very difficult to obtain radioactive irradiation - their penetrating power is only a few hundredths of a millimeter. On their way they create a very large number of pairs of ions, which provokes the formation of the strongest oxidants and releases hydrogen and oxygen.
Alpha radiation sources
Alpha decay is the main property of substances withheavy nuclei (plutonium-239, uranium-234, uranium-238, curium-244, americium-241). The shorter the half-life, the greater the energy and mileage of the alpha particle. That is why tens of thousands of years ago the natural radiation background of the planet was much higher than now. For medical purposes I use radium, radon, thorium.The influence of alpha particles on the human body
When they enter the biological environment, they causehigh linear ionization density, resulting in severe surface burns on the surface of the skin or mucous membrane. Only penetrating into the blood they are able to cause internal irradiation of the body. For example, accumulating in the pituitary and adrenal cortex, radon can cause disruption of the internal organs and reduce the adaptive properties of the body.The use of alpha radiation in medicine
The main source of alpha particles used inRadon treatment. The decay time is very short, and it is relatively easy to excrete from the body. Also for medicinal purposes, products of thoron and radium are used. Radon therapy is water bathing enriched radon, drinking of such water and air inhalation, wherein the desired particles are present. On Belokurikha resort, Gastein, Tskhaltubo, Pyatigorsk with radioactive natural healing factors, such procedures are traditionally used for the treatment of cardiovascular, endocrine and nervous systems, gynecological diseases and problems of the musculoskeletal apparatom.Dlya local impact with radiculitis, arthritis, neuritis , neurodermatitis, eczema use of applications from radioactive dressings. They obezbalivayut and soothe itch.Contraindications to alpha therapy
You can not use alpha particles whendiseases of blood, oncological diseases, pregnancy and tuberculosis. It is also worthwhile to refrain from radiotherapy to those who live in zones of increased radioactivity, as well as in high-altitude areas.Tip 6: What are radionuclides
The modern man is exposed daily to both artificial and natural sources of irradiation, which occurs as a result of radioactive decay of radionuclides.
