Radium, the element symbol Ra, is a kind ofradioactivityElements of[1], in chemistryperiodic table of ele mentsIt is located in the seventh period, the IIA family, and the atomic number is 88.Pure metallic radium is almost colorless, but when exposed to air, it willnitrogenThe reaction produces black radium nitride (RathreeNtwo）。All of radiumisotopeHave strongradioactivity, of which the most stable isotope isRadium-226，half lifeIt will decay into radon - 222 in about 1600 years.When radium decaysionizing radiationTo make the fluorescent material emit light.It is a new element jointly discovered by Curie and his wife. The discovery of radium has made great contributions to science.
On October 27, 2017, the list of carcinogens released by the International Agency for Research on Cancer of the World Health Organization (WHO) was preliminarily collated and referred to. Radium-224, Radium-226, Radium-228 and their decay products were included in the list of Class I carcinogens.
Chinese name
radium
Foreign name
radium
Alias
Barium like
chemical formula
Ra
CAS login number
7440-14-4
EINECS login number
231-122-4
Melting point
960 ℃
Boiling point
1737 ℃
Water solubility
React with water
Density
6 g/cm³
Appearance
Silver white soft metal
Application
Treat cancer
Security description
High radioactivity
Discoverer
Curie couple
Atomic number
eighty-eight
half life
About 1600 years (radium-226)
Oxidized state
+2
Period
Seventh cycle
Number of families
Group IIA (alkaline earth metal)
area
S area
Electronic layout
[Rn]7stwo
Atomic weight
two hundred and twenty-six point zero two five four
He was born on May 15, 1859, in a doctor's family in Paris, France.During his childhood and adolescence, he had a good personality of personal meditation, was not easy to change his mind, was silent, slow in reaction, was not suitable for the infusion type knowledge training in ordinary schools, and could not follow the class. People said that he was mentally retarded, so he never entered primary and secondary schools since childhood.His father often took him to the countryside to collect animal, plant and mineral specimens, which cultivated his strong interest in nature and learned how to observe things and how to interpret them.When Curie was 14 years old, his parents hired a math and science teacher for him. He made rapid progress in math and science. At the age of 16, he was admitted to a bachelor's degree in science. Two years after he entered the University of Paris, he obtained a master's degree in physics.In 1880, when she was 21 years old, she and his brother Jacques Curie studied the characteristics of crystals and found thatPiezoelectric effect。In 1891, he studied the relationship between the magnetism of matter and temperature and established Curie's law: the magnetization coefficient of paramagnetic matter is inversely proportional to the absolute temperature.In his scientific research, he also created and improved many new instruments, such as piezoelectric crystal scales, Curie scalesCurie electrometerEtc.Pierre Curie married Marie Curie on July 25, 1895.
Maria Sk ł odowska Curie[6]Born on November 7, 1867, in Warsaw under the rule of Tsar Russia, his father was a middle school teacher.At the age of 16, she graduated from Warsaw Middle School with a gold medal. Because her family was unable to support her to continue her studies, she had to work as a tutor for six years.Later, with a little savings and the help of my sister, I went to Paris to study in 1891.At the University of Paris, she studied hard under extremely difficult conditions. After four years, she obtained two master's degrees in physics and mathematics.
In 1896, the year after the Curie couple got married,BecquerelDiscovered uranium saltRadioactive phenomenonThis aroused the great interest of the young couple, and Madame Curie was determined to study the essence of this unusual phenomenon.She first examined all known chemical elements at that time and found that thorium and thorium compounds were also radioactive.She further examined the radioactivity of various complex minerals, and accidentally found that the radioactivity of pitchblende was higher than that of pureUranium oxideMore than four times stronger.She concluded that,uranium oreIn addition to uranium, there is obviously a more radioactive element.
Curie, based on his experience as a physicist, immediately realized the importance of this research achievement, put down the crystal research he was engaged in, and joined Madame Curie in finding new elements.Soon after, they determined that there was not one element in the uranium ore, but two undiscovered elements.In July 1898, they first named one element polonium in memory of Madame Curie's motherland Poland.Before long, in December 1898, they named another element radium.They worked hard to get pure polonium and radium.In a dilapidated shed, I worked day and night for three years and nine months.He used an iron bar to stir the boiling asphalt uranium slag in the pot, and his eyes and throat were stimulated by the smoke from the pot. After refining again and again, he got one tenth of a gram of radium from several tons of asphalt uranium slag.Due to the discovery of radioactive substances, the Curies and Becquerel jointly obtainedThe nobel prize in physics。
Marie Curie discovered a chemical element radium, chemical symbol Ra, atomic number 88, atomic weight 226.0254, belonging to periodic system IIA groupalkaline-earth metalMembers andNatural radioactive element。In December 1898, Marie Curie and Pierre CuriePitchblendeUranium extractedslagSeparated fromRadium chlorideIn 1907, the new atomic weight of radium was measured, and in 1910, the metal radium (white metal) was made by electrolytic chlorination of radium. Its English name comes from Latin radius, meaning "ray".The content of radium in the crust is 1 × 10-9%, which has been found so farMass numberAmong the isotopes ranging from 206 to 230, except radium-223, radium-224, radium-226 and radium-228Natural radioisotopeIn addition, the rest are artificially synthesized.Radium exists in allUranium oreEach 2.8t uranium ore contains 1g radium.
A brief history of discovery
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After Berkler's pioneering observation and research on the radioactive properties of uranium, he found that uranium rays are also like X-rays, which can make air and other gases conductive, while thorium compounds have also been found to have similar properties.Since 1896, Madame Curie and her husband have made systematic discoveries[2], looking for this effect in various elements, their compounds and natural products.
Becquerel phenomenon, which aroused the strong interest of the Curies. Where did the power of radiation come from?What is the nature of this radiation?
Madame Curie devoted her whole body and mind to the research of uranium salt. She extensively searched and studied various uranium salt ores. She was attracted by the magic rays of uranium salt ores. She dedicated her special love to this special ore.
Madame Curie, who had received strict and systematic higher chemical education, thought when studying uranium salt ores that there was no reason to prove that uranium was the only chemical element that could emit radiation.She guessed that there must be other elements with the same power, but people did not know it.
She's based on Mendeleev'sPeriodic law of elementsThe arrayed elements were measured one by one, and it was soon found that the compound of another thorium element also automatically emitted rays, similar to uranium rays, and the intensity was also close.
Madame Curie realized that this phenomenon was by no means just a characteristic of uranium. It must be given a new name. Madame Curie named it "radioactive". Uranium, thorium and other substances with this special "radioactive" function are called“radioactive element”。
Later, with the help of her husband, Mr. Pierre, she measured all the minerals that could be collected. She wanted to know which other minerals were radioactive.
In the measurement, she got another dramatic discovery. In a pitchblende from Bohemia, she found that its radioactive intensity was many times greater than originally thought.
So, where does this abnormal and excessive radioactivity come from?The amount of uranium and thorium in these pitchblende ores can never explain the intensity of radioactivity she observed.
Therefore, there can only be one explanation. These asphalt minerals contain a new element that is much stronger than the radioactivity of uranium and thorium, and it is not an element known by humans at that time. It must be an unknown element.
Madame Curie's discovery attracted Mr. Pierre's attention. Together, the Curies launched a powerful attack on the unknown field of science.
In the laboratory with extremely poor conditions, the Curie couple announced the discovery of this new element in July 1898, which was 400 times more radioactive than pure uranium, through their unremitting long-term efforts.
In memory of her suffering motherland, the new element was named polonium (meaning Poland).
In December 1898, the Curies announced that they had discovered a second radioactive element based on a large number of experimental facts. This new element was more radioactive than polonium. They named this new element "radium".
However, since there were no samples of polonium and radium and no atomic weights of polonium and radium, few people in the scientific community at that time were willing to believe their shocking new discovery.
The Curies were determined to extract samples of polonium and radium no matter what price they paid, on the one hand to confirm their existence, and on the other hand, to make themselves more confident.
The Curie couple are a pair of intellectuals who are in financial difficulties. They cannot afford to buyPitchblendeThe high cost required.But they were not intimidated by the "road block" in front of them. They almost tried all kinds of ways.
After countless setbacks, the Austrian government officially decided to donate a ton of slag to the Curies and promised that if they needed a large amount of slag in the future, they could supply it under the most favorable conditions.
Madame Curie immediately threw herself into the heavy work of extraction. She put more than 20 kilograms of waste slag into the smelting pot for heating and melting each time, stirred the boiling slag liquid continuously for several hours with a thick iron bar, and then extracted the trace substance containing only one millionth.
From 1898 to 1902, after countless times of extraction and treatment of nearly a ton of ore residue, 0.1 g of radium salt was finally obtained, and its atomic weight was determined to be 226.
The discovery of radium broke out a real revolution in the scientific community. In 1903, the Curies both won the Nobel Prize in Physics for it.Madame Curie's great success is by no means easy to achieve. It is the crystallization of the joint efforts of the Curies, which embodies their sweat and tears.
Density 6.0g/cmthree（20℃）[1], melting point 700 ℃, boiling point about 1140 ℃.Silver white lustrous soft metal.It is unstable in the air and easy to combine with nitrogen and oxidation in the air.React with water to release hydrogen and generateRadium hydroxideRa(OH)two。Soluble in dilute acid.Chemical properties are very similar to barium;All radium salts are isomorphic with the corresponding barium salts.Radium can generate sulfate, carbonatechromateIodate;RadiumchlorideBromidehydroxideSoluble in water.It is known that radium has 13 isotopes,two hundred and twenty-sixRahalf lifeThe longest is 1622.
The following are various reactions of radium
Reaction with nitrogen: 3Ra+Ntwo=RathreeNtwo
Reaction with oxygen: 2Ra+Otwo=2RaO
Reaction with sulfur: Ra+S=RaS
Reaction with halogen: Ra+Ftwo=RaFtwo；Ra+Cltwo=RaCltwo；Ra+Brtwo=RaBrtwo；Ra+Itwo=Raltwo
Reaction with water:
Introduction to Radium
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Radium symbol Ra, atomic number 88, atomic weight 226.03.Peripheral electronic layout for 7stwo, density 6.0g/cmthree, melting point 700 ℃, boiling point<1140 ℃, located in the seventh cycle, group IIA.Silver white lustrous soft metal.The first ionization energy is 509.37 kJ/mol, and the electronegativity is 0.9.Active chemical property, unstable in the air, easy to follownitrogenandoxygencompound.React with water to produce radium hydroxide (Ra (OH))two）And release hydrogen.Soluble in dilute acid.Chemical properties are very similar to barium.Radiumchloride、Bromide、hydroxideSoluble in water,sulfate、carbonateSlightly soluble in water.It is known that there are many kinds of radiumisotope, Radium-226half lifeThe longest is 1622.Radium is highly radioactive. It emits alpha and gamma rays when it decays, and emits a lot of heat (586.18J per gram of radium per hour). It splits to produce hydrogen and nitrogen.Under the irradiation of radium, water, ammoniaHydrogen chlorideIt can be decomposed, and oxygen can be converted into red oxygen.Zinc sulfide、Calcium sulfideSuch alkaline earth metal sulfide can emit light green and soft phosphorescence under the irradiation and excitation of radium ray.Radium rays can destroy animals and kill cells and bacteria.It can cure cancer by using radium radiation. It can be made by mixing 10ppm radium salt into zinc sulfide and calcium sulfideLuminous paint、Luminous plastic。Radium saltBeryllium powderMixed preparation of, which can be used as neutronRadioactive Source, used to detect oil resources and rock composition.Radium in naturecompound formIt mainly exists in a variety of minerals, soil, mineral water and seabed silt.Radium is extremely rare in nature, accounting for only 8/10 billion of the total number of atoms in the earth's crust.In 1898, French scientist Curie and his wifePitchblendeIn 1910, Madame Curie made pure metal radium from pitchblende.The Greek original of radium is ray.The radium mercuric agent can be obtained by electrolysis of radium chloride solution with mercury cathode and palladium iridium anode, and then carried out in hydrogenthermal decompositionMade.
A chemical element.Chemical symbolRa，Atomic number88, atomic weight 226.0254, belonging to periodic system IIA groupalkaline-earth metalMembers of the and natural radioactive elements.In 1898, M. Curie and P. Curie separated radium bromide from the slag after extracting uranium from pitchblende. In 1910, they produced metal radium by electrolytic chlorination of radium. Its English name comes from Latin radius, meaning "ray".Radium is a fluorescent blue/silver white metal, which is the most active alkaline earth metal.Radium can quickly interact withnitrogenandoxygenGenerate radium nitride (RatwoNthree）AndRadium oxide(RaO), react violently with water, generateRadium hydroxideAnd hydrogen.The outermost electron layer of radium has two electrons,Oxidized stateIs+2, and only compounds with+2 valence are formed.Radium salts and corresponding barium salts are isomorphic compounds,chemical propertyVery similar.Radium chloride、Radium bromide、Radium nitrateAre easily soluble in water,Radium sulfateRadium carbonate and radium chromate are insoluble in water.Radium is highly toxic. It can replace calcium in human body and concentrate in bones. Acute poisoning will cause damage to bone marrow and serious damage to hematopoietic tissue. Chronic poisoning can cause osteoma and leukemia.Radium is a by-product of uranium productionuranium oreWhen uranium is leached in the medium, radium becomessulfateIt exists in slag, and then it is converted into radium chloride, and the pure radium salt can be obtained by fractional crystallization with barium salt as the carrier.Metal radium is produced by electrolysisRadium chlorideMade.Radium and its decay product emissionGamma rayIt can destroy the malignant tissues in the human body, so radium can cure cancer, but it can also destroy the benign tissues in the human body.
Element Source
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It exists in a variety of ores and mineral springs, but the content is extremely rare, and most of them come from pitchblende.When extracting uranium from pitchblende, radium is often recovered together with barium in the form of sulfate in the acid insoluble residue. At that time, the Curies spent three years and nine months refining 0.1 grams of radium[1]。
Decay of radium
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Radioactive elements will produce different substances after decay for a period of time (different decay rates of various elements).Radium is one of them.
Decay rate of radium
The decay rate of radium is proportional to its existing quantity R: dR=R λ dt → dR/R=λ dt → LnR=Ceλt
t=0，R=Rzero→R=Rzeroeλt
After 1600 years of radium, only the original amount R remainszero1/2 → 1/2=e1600λ→ λ=(-Ln2)/1600 → R=Rzeroe(-Ln2)*t/1600
α decay equation of radium
Alpha equation of radium:
purpose
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Radium can emit alpha and gamma rays and generate radioactive gasesradon。
Radium can destroy and kill cells and bacteria.Therefore, it is often used to treat cancer.In addition, the mixed preparation of radium salt and beryllium powder[4]It can be used as neutron radiation source to detect oil resources, rock composition, etc.
Radium is one of the materials of the atomic bomb.Old-fashionedFluorescent coatingIt also contains a small amount of radium.Neutron bombardment radium-225 can obtainActinium。
