Compounds Containing A Metal Ion With A Variable Charge
Most of the transition metals can form two or more cations with different charges. Compounds of these metals with nonmetals are named with the same method as compounds in the first category, except the charge of the metal ion is specified by a Roman numeral in parentheses after the name of the metal. The charge of the metal ion is determined from the formula of the compound and the charge of the anion. For example, consider binary ionic compounds of iron and chlorine. Iron typically exhibits a charge of either 2+ or 3+ , and the two corresponding compound formulas are FeCl2 and FeCl3. The simplest name, iron chloride, will, in this case, be ambiguous, as it does not distinguish between these two compounds. In cases like this, the charge of the metal ion is included as a Roman numeral in parentheses immediately following the metal name. These two compounds are then unambiguously named iron chloride and iron chloride, respectively. Other examples are provided in;Table;4.
|Table;4. Names of Some Transition Metal Ionic Compounds|
|Transition Metal Ionic Compound|
Design Origin And Terminology
Lithium polymer cells have evolved from lithium-ion and lithium-metal batteries. The primary difference is that instead of using a liquid lithium-salt electrolyte held in an organic solvent , the battery uses a solid polymer electrolyte such as poly , poly , poly or poly .
The solid electrolyte can typically be classified as one of three types: dry SPE, gelled SPE and porous SPE. The dry SPE was the first used in prototype batteries, around 1978 by Michel Armand, and 1985 by ANVAR and Elf Aquitaine of France, and Hydro Quebec of Canada. From 1990 several organisations like Mead and Valence in the United States and GS Yuasa in Japan developed batteries using gelled SPEs. In 1996, Bellcore in the United States announced a rechargeable lithium polymer cell using porous SPE.
A typical cell has four main components: positive electrode, negative electrode, separator and electrolyte. The separator itself may be a polymer, such as a microporous film of polyethylene or polypropylene ; thus, even when the cell has a liquid electrolyte, it will still contain a “polymer” component. In addition to this, the positive electrode can be further divided into three parts: the lithium-transition-metal-oxide , a conductive additive, and a polymer binder of poly . The negative electrode material may have the same three parts, only with carbon replacing the lithium-metal-oxide.
How Is Phosphorus Used In Everyday Life
Phosphorus is a essential nutrient in plants and its main use through phosphate compounds is in fertilizer production. Just as there are biological cycles of carbon and nitrogen, there is a phosphorus cycle. Phosphorus is used for the production of safety matches , pyrotechnics, and fire shells.
Occurrence In Humans And The Biosphere
Polonium-210 is widespread in the biosphere, including in human tissues, because of its position in the uranium-238 decay chain. Natural uranium-238 in the Earth’s crust decays through a series of solid radioactive intermediates including radium-226 to the radioactive noble gas radon-222, some of which, during its 3.8-day half-life, diffuses into the atmosphere. There it decays through several more steps to polonium-210, much of which, during its 138-day half-life, is washed back down to the Earth’s surface, thus entering the biosphere, before finally decaying to stable lead-206.
As early as the 1920s, French biologist Antoine Lacassagne;, using polonium provided by his colleague , showed that the element has a specific pattern of uptake in rabbit tissues, with high concentrations, particularly in liver, kidney, and testes. More recent evidence suggests that this behavior results from polonium substituting for its congener sulfur, also in group 16 of the periodic table, in sulfur-containing amino-acids or related molecules and that similar patterns of distribution occur in human tissues. Polonium is indeed an element naturally present in all humans, contributing appreciably to natural background dose, with wide geographical and cultural variations, and particularly high levels in arctic residents, for example.
How Dangerous Is It
Polonium does not have toxic chemical properties. The danger comes when it emits radiation.
Toxicologists estimate that one gram of polonium-210 could be enough to:
- kill 50 million people
- make another 50 million people ill
Litvinenko could have died after consuming less than one millionth of that amount.
As a weapon, it would be lethal. But it is also extremely difficult to obtain. When used in commercial devices, this is done in such a way that the polonium could not be separated for use as a poison.
Even if someone did manage to acquire some polonium, it is not particularly dangerous to carry around, because its high-energy radiation can be blocked by a relatively thin barrier, such as a piece of paper.
Polonium-210 cannot penetrate the skin, and the particles usually lose all their energy after traveling through a few centimeters of air.
However, this also makes it safe to transport and hard to detect, for a would-be poisoner.
To poison someone, however, it must then be introduced to the body.
This can be done through:
- Entry through skin abrasions or wounds.
A person by another, contaminated person unless they swallow or inhale bodily fluids from that person.
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Certain Facts About Polonium
- The lady, Marie Curie named this element after her native land of Poland. Poland was not an independent country then and was ruled by Russian, German, and Austro-Hungarian partition. With a hope naming the element after her native land would publicize its lack of independence, Madam Curie did so. It can be said that Polonium was the first element ever to be named to highlight a political controversy.
Detection In Biological Specimens
Polonium-210 may be quantified in biological specimens by alpha particle spectrometry to confirm a diagnosis of poisoning in hospitalized patients or to provide evidence in a medicolegal death investigation. The baseline urinary excretion of polonium-210 in healthy persons due to routine exposure to environmental sources is normally in a range of 515 mBq/day. Levels in excess of 30 mBq/day are suggestive of excessive exposure to the radionuclide.
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The Other Group 16 Elements: S Se Te And Po
A general chemistry;Libretexts;Textmap;organized around the textbookChemistry: Principles, Patterns, and Applicationsby Bruce A. Averill
I ;;II ;;III;;;;IV;;;V;;;;VI ;;VII;;;;VIII;;;;IX;;X;;;XI;;;XII;;XIII ;;XIV;;;XV ;;XVI ;;XVII;;;XVIII;;;XIX;;;XX ;;;XXI;;;;XXII;;XXIII;;XXIV;Homework
- To understand the trends in properties and reactivity of the group 16 elements: the chalcogens.
The chalcogens are the first group in the p block to have no stable metallic elements. All isotopes of polonium , the only metal in group 16, are radioactive, and only one element in the group, tellurium , can even be described as a semimetal. As in groups 14 and 15, the lightest element of group 16, oxygen, is found in nature as the free element.
Group 16 is the first group in the p block with no stable metallic elements.
Tellurium was discovered accidentally in 1782 by the Austrian chemist Franz Joseph Müller von Reichenstein, the chief surveyor of mines in Transylvania who was also responsible for the analysis of ore samples. The silvery-white metal had the same density as antimony but very different properties. Because it was difficult to analyze, Müller called it metallum problematicum . The name tellurium was coined by another Austrian chemist, Martin Klaproth, who demonstrated in 1798 that Müllers difficult metal was actually a new element. Tellurium is used to color glass and ceramics, in the manufacture of blasting caps, and in thermoelectric devices.
Jöns Jakob Berzelius
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Health Effects Of Polonium
Polonium is studied in a few nuclear research laboratories where its high radioactivity as an alpha-emitter requires special handling techniques and precautions.
Polonium -210 is the only component of cigarette smoke that has produced cancer by itself in laboratory animals by inhalation – tumors appeared already at a polonium level five times lower than those of a normal heavy smoker.
Lung cancer rates among men kept climbing from a rarity in 1930 to the No. 1 cancer killer in 1980 in spite of an almost 20 percent reduction in smoking. But during the same period, the level of polonium -210 in American tobacco had tripled. This coincided with the increase in the use of phosphate fertilizers by tobacco growers – calcium phosphate ore accumulates uranium and slowly releases radon gas.
As radon decays, its electrically charged daughter products attach themselves to dust particles, which adhere to the sticky hairs on the underside of tobacco leaves. This leaves a deposit of radioactive polonium and lead on the leaves. Then, the intense localized heat in the burning tip of a cigarette volatilizes the radioactive metals. While cigarette filters can trap chemical carcinogens, they are ineffective against radioactive vapors.
What Are Chemical Equations
They are equations that make use of chemical formulae and symbols to represent chemical reactions. The left-hand side of a chemical equation represents the reactants and the right-hand side represents the products. These entities are separated by a symbol that describes the direction of the reaction. Each reacting entity is also assigned its corresponding stoichiometric coefficient.
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Who / Where / When / How
- Named after Poland, the home country of Marie Curie.
- Occursin trace amounts in uranium ores. World wide production is very small and probably less than 100 grams per year.
- Used for nuclear batteries, neutron source, antistatic agents, film cleaner.
What Is A Chemical Equation
Chemical equations are symbolic representations of chemical reactions in which the reactants and the products are expressed in terms of their respective chemical formulae. They also make use of symbols to represent factors such as the direction of the reaction and the physical states of the reacting entities. Chemical equations were first formulated by the French chemist Jean Beguin in the year 1615.
Chemical reactions can be represented on paper with the help of chemical equations, an example for which is represented below .
2H2 + O2 2H2O
It can be observed in the example provided above that the reacting entities are written on the left-hand side whereas the products that are formed from the chemical reactions are written on the right-hand side of the chemical equation.
It can also be observed that there are coefficients assigned to each of the symbols of the corresponding reactants and products. These coefficients of entities in a chemical equation are the exact value of the stoichiometric number for that entity.
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How To Locate Polonium On Periodic Table
Periodic table is arranged by atomic number, number of protons in the nucleus which is same as number of electrons. The atomic number increases from left to right. Periodic table starts at top left and ends at bottom right . Therefore you can directly look for atomic number 84 to find Polonium on periodic table.
Another way to read periodic table and locate an element is by using group number and period number . To locate Polonium on periodic table look for cross section of group 16 and period 6 in the modern periodic table.
Explore Interactive Periodic Table to Understand and Learn Cool Trends
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Radio Controlled Equipment And Aircraft
LiPo batteries are now almost ubiquitous when used to power radio-controlled aircraft, radio-controlled cars and large scale model trains, where the advantages of lower weight and increased capacity and power delivery justify the price. Test reports warn of the risk of fire when the batteries are not used in accordance with the instructions.
The voltage for long-time storage of LiPo battery used in the R/C model should be 3.6~3.9V range per cell, otherwise, otherwise it may cause damage to the battery.
LiPo packs also see widespread use in airsoft, where their higher discharge currents and better energy density compared to more traditional NiMH batteries has very noticeable performance gain . The high discharge currents do damage the switch contacts due to arcing , so it is advised to either use a solid-stateMOSFET switch or clean the trigger contacts regularly.
Chemical And Physical Properties Of Polonium
- Ph.D., Biomedical Sciences, University of Tennessee at Knoxville
- B.A., Physics and Mathematics, Hastings College
Polonium is one of the radioactive elements discovered by Marie and Pierre Curie. This rare element has no stable isotopes. It’s found in uranium ores and cigarette smoke and also occurs as a decay product of heavier elements. Although there aren’t many applications for the element, it is used to generate heat from radioactive decay for space probes. The element is used as a neutron and alpha source and in anti-static devices. Polonium has also been used as a poison to commit assassinations. Although the position of element 84 on the periodic table would lead to categorization as a metalloid, its properties are those of a true metal.
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What Is An Ionic Equation
The chemical equations in which electrolytes are represented in the form of dissociated ions are commonly referred to as ionic equations. They are often used to represent the displacement reactions that take place in aqueous mediums. In these reactions, some ions participate in the reaction and some do not. The ions that do not react are called spectator ions and are usually omitted from the net ionic equation.
More Information Onmolar Mass And Molecular Weight
In chemistry, the formula weight is a quantity computed by multiplying the atomic weight of each element in a chemical formula by the number of atoms of that element present in the formula, then adding all of these products together.
If the formula used in calculating molar mass is the molecular formula, the formula weight computed is the molecular weight. The percentage by weight of any atom or group of atoms in a compound can be computed by dividing the total weight of the atom in the formula by the formula weight and multiplying by 100.
Using the chemical formula of the compound and the periodic table of elements, we can add up the atomic weights and calculate molecular weight of the substance.
Finding molar mass starts with units of grams per mole . When calculating molecular weight of a chemical compound, it tells us how many grams are in one mole of that substance. The formula weight is simply the weight in atomic mass units of all the atoms in a given formula.
The atomic weights used on this site come from NIST, the National Institute of Standards and Technology. We use the most common isotopes. This is how to calculate molar mass , which is based on isotropically weighted averages. This is not the same as molecular mass, which is the mass of a single molecule of well-defined isotopes. For bulk stoichiometric calculations, we are usually determining molar mass, which may also be called standard atomic weight or average atomic mass.
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High Radioactivity High Lethality
Polonium is a highly radioactive heavy metal. It is arguably the most lethal known material. Although it has some minor industrial uses it is best known for links with possible assassinations. It is also used to produce neutrons in the core of nuclear weapons.
Discovered by , the element was named after her home country of Poland. Polonium is element 84 in the periodic table, and all of its isotopes are radioactive. Their half-lives vary between a few millionths of a second to 103 years.
When polonium is discussed in the media, it is usually in the context of the polonium-210 isotope . This isotope has a half-life of 138 days, so while the material has very high radioactivity, it is stable enough to be transported .
210Po has been suggested as a method of assassination. The two most famous suspected cases being KGB-agent-turned-journalist Alexander Litvinenko in 2006 and as mentioned above Yasser Arafat.
As air reacts with alpha particles, the polonium must be ingested into the assassination target. In the case of Litvinenko it is alleged that was given to him in a cup of tea.
The 138-day half-life of 210Po is short, so the element is very radioactive. While it has a melting point of 254°C, it is so radioactive that if you made 1g piece of 210Po it would create so much heat it would melt itself. The liquid would appear to glow blue due to the interaction of the alpha particles with the surrounding air.