Nobellium (No): Features, Receipts, History

The Nobleium, Symbol number and atomic number 102, a chemical element belonging to the actinide group of the periodic table. Despite having 12 isotopes, with a 58-minute half-life, nobellium is not found in nature, being synthesized in the laboratory. Although a metallic sample of No has never been made, it is known that the solution of this material always has a +2 charge.

The Nobellium, which honors the Swedish Alfred Nobel, is an element of the history of discovery marked by conflict and contradiction. Until it was formalized by IUPAC, this element was the protagonist of the clash between American, Russian, British and Swedish scientists in a typical episode of the Cold War in the history of science.

Learn more: Lorentius – The chemical element named after scientist Ernest Orlando Lawrence

The subject of this article

Summary of Nobleium

  • Noblelium is a chemical component that belongs to the periodic table actinides.

  • It has 12 known isotopes, 259Not the most stable.

  • In solution, it has an oxidation number equal to +2.

  • Its chemical behavior is close to heavy alkaline earth metals like strontium, barium and radium.

  • It is not found in nature, so it is a synthetic chemical that is made in the laboratory by nuclear fusion reactions.

  • Its initial discovery was described by a group of Stockholm scientists, but due to several contradictions, the IUPAC 102 recognized Russian competence in the discovery of the material.

Don’t stop now … there’s more after the promotion;)

Features of Noblelium

  • Symbol: A.

  • Atomic number: 102

  • Molecular mass: 259 one

  • Electronic configuration: [Rn] 7 SheTwo 5f14

  • The most stable isotope: Two59No (58 minutes half-life)

  • Chemical series: Actinides

Features of Noblelium

Nobleium, symbol number and atomic number 102, a Ingredients of actinide. In terms of its atomic structure, the nobellium does not present a stable enough isotope to detect a natural source. 259No (with 58 minutes), then 255No (with 3.1 minutes).

Therefore, to study Nobellium, it needs to be made in a laboratory, using a particle accelerator to cause a nuclear fusion reaction to occur, which characterizes it as a. Synthetic chemical ingredients. The 255 isotope is the most widely used even in chemical studies, presenting, among all isotopes, the highest production rate.

One despite the consideration Metal, A metallic specimen of the element noblelium was never produced. However, its chemistry in solution is further discussed: although other actinide aqueous solutions have +3 charges, noblelium +2 represents the oxidation state as the most stable.

One such property was predicted by Glenn Seiberg in 1949, since the electronic distribution ended at 5f.14 7 SheTwoIt would be more interesting for Nobleium to lose only two electrons and keep a 5f subshell14 Filled

In 1968, about 600 tests were performed, including 50,000 atoms 255They were not heroes, they were aimed at raining down on certain compounds. The results show that there was no Chemical behavior is closer to alkaline earth metal (Strontium, barium and radium) Compared to the trivalent actinide, the 2+ ions of No would be the most stable species for this element.

Receipt of Noblelium

Noblelium is not found in nature, its production is required in the laboratory. Isotope 255No, most commonly used in chemical research, It can be found Through Fusion reaction Atomic By bombing 249Cf for its ions 12.

({_ 6 ^ {12}} C + frac {249} {98} Cf frac {255} {102} No + {_ 2 ^ 4 alpha + 2 {_0 ^ 1} n )

After 10 minutes of testing the average yield is about 1200 atoms. Noblelium produced can be distinguished from other actinides, which, in turn, can be produced in the process by column chromatography.

Also read: Teneso – Another synthetic chemical derived from nuclear fusion

History of Noblelium

Noblelium, despite not having many practical features for us in everyday life, was the protagonist of a great controversy among scientists about its discovery. It was a start Episodes of the Cold War in the history of science And gives Periodic tableWhich later developed into a war of attrition.

Until then, the synthesis of extremely heavy elements was predominant by California scientist Glenn Seiberg and his team of nuclear physicists and chemists. However, in 1957, A team of scientists has claimed to have created two isotopes of 102 elements Curium detonates atoms (244Cm) with ions 13C. The team consisted of Swedish, British and American scientists from the Nobel Institute for Physics in Stockholm.

From there, Stockholm physicists announced new transuranic elements with the No. symbol, GrantedHim The name Noblelium in honor of the legacy of Alfred Nobel. The discovery was widely reported in the press at the time, including in the famous newspaper. Svenska DagbladetFrom Sweden, and GuardianFrom England.

Alfred Nobel, Swedish chemist and inventor honored by the discovery of 102 elements.

However, there was something beyond scientific interest behind the discovery, as the English scientist John Millsted, who worked at the Stockholm Group, said: The scientist made a reference to Soviet scientists from the Russian city of Dubna.

However, later Discovery of the Swedish-British-American team Showed himself InsufficientThis allowed the distrust of rival laboratories of both the Soviets and the Americans to grow, leading them to accept responsibility for discovering the truth of 102 elements.

The Americans from Berkeley, led by Glenn Seiberg and Albert Ghiorso, initially assumed that Stockholm’s works were correct, after all, they were published in a reputable scientific journal. Physical review. However, at no time was it possible to reproduce the tests conducted in Stockholm.

Ironically, American groups have even suggested names nobelievium 102 as something more appropriate for the material (gently translated “I do not believe”). In 1958, Ghiorso, along with Seiberg, scientists Torbjorn Seekeland and John Walton, announced the creation of isotopes. 254Not by bombers 246Ions per cm 12C, and thus requesting recognition for the discovery of element 102.

The Stockholm Group acknowledged that the results obtained at Berkeley cast some doubt on their own results, but a new analysis and explanation in 1959 showed that the suspicion was simply clear.

In addition, Stockholm Group results cannot be reproduced By Soviet scientist Georgi Flerov and his colleagues at the Moscow Kurchatov Institute in Dublin. Russian scientists did not believe them in Stockholm, except to claim that the American experiments were only an indication of 102 elements.

The Russians had already synthesized 102 elements, through bombings in 1957 and 1958 241Pu with ions 16O, without necessarily gaining recognition for discovery. Subsequent experiments, however, which lasted until 1966, provided more compelling evidence for the existence of isotopes of this element. From there, Flavor pointed out inconsistencies in Berkeley’s writings and claimed that Nobleium The experiments, which took place between 1963 and 1966, were discovered in Dubna.

Despite much conflict between the Russian and American sides, the Dubna group did not propose a different name for Nobellium, although the Americans wanted to do so, as it would be interesting to choose a name that better reflects their discovery.

Nevertheless, the International Union of Pure and Applied Chemistry (IUPAC), in 1961, officially introduced the entry of element 102 in the name of Nobellium, but without mentioning any isotope or atomic mass, which is a sign of uncertainty at the time. However, it did allow for the popularization of Nobleium in books and periodic tables, and so Americans abandoned giving the material a new name.

The Russians, refusing to call the new element Nobellium, suggested the name Joliotium, the symbol Jl, referring to the French physicist and Nobel laureate Frederick Joliet-Curie (married to Irene Joliet-Curie, daughter of Marie Curie and Pierre Curie). In the USSR, the name Joliotium was a favorite, considering that Frederick Joliot-Curie was a devout communist.

In the late 1990’s, IUPAC solved the problem of naming superheavy components, blaming the Dubna Group for producing 102 components. However, the adopted name was Noblelium, which had the symbol number.

Exercises solved in noblelium

Question 1

Nobleum, atomic number 102, contains 12 isotopes. Of these, the most stable isotope 259No, with a half-life of 58 minutes. Imagine a process of synthesis of this isotope, how many minutes does it take for its mass to decay at one-eighth of the initial mass?

A) 58 minutes

B) 116 minutes

C) 174 minutes

D) 232 minutes

E) 290 minutes

Resolution:

Option c

Half-life is the time required to halve the sample size. After 58 minutes, the isotope mass 259As the initial mass is 6, it does not fall in half. After another 58 minutes, the isotope mass 259As the initial mass is 6, it does not fall again.

Thus, more than 58 minutes (three half-lives in total), its mass 259It does not fall in half again, 1/8 of its initial mass. Therefore, the total time is 3 x 58 = 174 minutes.

Question 2

Although not the most stable, the isotope 255 (Z = 102) of Nobelium is the most widely used and produced in the laboratory. How many neutrons does an isotope make? 255Don’t own?

A) 255

B) 102

C) 357

D) 153

E) 156

Resolution:

Option d

The number of neutrons can be calculated as follows:

A = Z + n

Where A is the number of atomic masses, Z is the number of protons (or atomic number) and n is the number of neutrons. To replace the standard, we have:

255 = 102 + n

n = 255 – 102

n = 153

By Stefano Araujo Novice
Chemistry teacher

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