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Ununpentium – Introduction, Discovery, History, Nuclear Stability, Isotopes, Properties, Practice Problems and FAQ

Ununpentium – Introduction, Discovery, History, Nuclear Stability, Isotopes, Properties, Practice Problems and FAQ

Let’s hear an interesting story about Ununpentium, or the element with Atomic number – 115. 

It was only in 2003, that ununpentium was artificially synthesised by scientists in a laboratory. But for more than decades, this element has been linked under a special connection with UFOs, aliens and other related phenomena! Thrilling isn't it! Let’s see how it goes.

This is in reference to a long-lived story of Bob Lazar, who in 1989 went public with what he claimed to be extremely confidential information about Element-115. Lazar claimed to be a former employee at Area 51, the hidden think tank of the Nevada Test and Training Range operated by the United States Air Force, where he was a reverse-engineering professional who studied crashed alien flying saucers. He claimed to have worked with element 115, which was used to pilot extraterrestrial spacecraft.

To quote him, " It was impossible to synthesise an element that heavy here on Earth. The substance has to come from a place where super-heavy elements could have been produced naturally," 

Lazar also claimed to have seen anti-gravity technology and nine alien spacecraft stored in a hangar at Area 51. When the great Dmitri Mendeleev organised the Periodic Table with around fifty nine element entries, he also kept thirty-three empty spaces for probable future elements. By 1939, all of Mendeleev’s boxes had been filled. But what he could never have imagined was that scientists would one day begin creating elements not found naturally. 

Let’s find out more about this interesting element, that is not naturally available and is synthesised (at least on earth!) by humans.


  • What is Ununpentium?
  • History and Discovery
  • Nuclear Stability and Isotopes
  • Probable Properties
  • Physical and Atomic Characteristics
  • Fundamental Data
  • Chemical Properties
  • Uses
  • Practice Problems
  • Frequently Asked Questions - FAQ

What is Ununpentium?

Ununpentium is an example of a laboratory-created synthetic element. It was first synthesised in 2003 at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia, by a joint team of Russian and American scientists. Due to its restricted manufacturing and availability, Ununpentium is only utilised in fundamental studies.

The Joint Working Party of international scientific bodies IUPAC and IUPAP recognised it as one of four new elements in December 2015. It was officially named “Moscovium’’ after the Moscow Oblast on November 28, 2016.

Moscovium (Mc) is a transuranium element with an atomic number of 115 in the modern periodic table that has been synthesised chemically. It is expected to be toxic, owing to its radioactivity and the likelihood that biological processes may displace other metals.

History and Discovery

In August 2003, a joint team of Russian and American scientists at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia, achieved the first successful synthesis of moscovium. The team was led by Russian nuclear physicist Yuri Oganessian that included scientists from Lawrence Livermore National Laboratory. 

  • The scientists mentioned that Ununpentium was synthesised by bombarding Americium-243 with Calcium-48 ions to produce four atoms of ununpentium (Moscovium). In about 100 milliseconds, these atoms decayed to nihonium by emitting alpha particles.
  • Moscovium is also known as eka-bismuth, which is based on Mendeleev's nomenclature for unnamed and undiscovered elements.
  • The systematic element name Ununpentium (with the corresponding symbol of Uup) was recommended by IUPAC in 1979 until the element's discovery was confirmed and a permanent name was determined.
  • In June 2016, IUPAC accepted the name proposal of "Moscovium", and the naming ceremony for Moscovium (Z=115), Tennessine ((Z=117), and Oganesson (Z=118) was held on March 2, 2017, at the Russian Academy of Sciences in Moscow.

Nuclear Stability and Isotopes

  • The isotopes of Moscovium 1 may be chemically investigated with current methods, although their short half-lives would make this challenging. 
  • Moscovium is the heaviest element that has known isotopes that are long-lived enough for chemical experimentation.
  • 1 is one of the stable isotopes with a half-life of 220 milliseconds.
  • Ununpentium or Element-115 also falls in the centre of the theoretical island of stability.
  • Although no stable isotopes have yet been found, conventional models predict that if stable isotopes of element 115 can be produced, they will most likely need the "magic number" of 184 neutrons, which would be Uup-299. 
  • The currently fabricated isotopes only have at most 173 neutrons (Uup-288), which is far short of 184 neutrons.
  • Moscovium is expected to have a range of stability lying between Copernicium (number 112 element) and Flerovium (number 114 element).
  • Because of the projected high fission barriers, every node of stability on this island of stability decays totally via alpha decay and perhaps some electron capturing and beta decay.

Probable Properties

Moscovium is a highly radioactive element with a half-life of only 0.65 seconds for its most stable known isotope, Moscovium-290. It belongs to the seventh period of the periodic table and is classified as the heaviest pnictogen in group 15.

Moscovium should have properties similar to that of thallium as both these elements contain a very closely packed electron on the outside of a quasi-closed shell.

Physical and Atomic Characteristics

  • Each former pnictogen contains five electrons in the valence shell, resulting in a ns2 np3 valence electron configuration.
  • In many ways, Moscovium will function similar to its family of pnictogens since the tendency must be constant as well as the valence electron arrangement is projected to be 7s2 7p3 in this case.
  • Significant variations are likely to emerge, with the (SO) spin-orbit interaction—the mutual interaction between the velocity and spin of electrons—playing a major role.
  • It is especially powerful for superheavy elements, since their electrons travel considerably faster than those of lighter atoms, at a rate close to that of light.
  • It lowers the 7s and 7p electron energy levels with respect to moscovium particles (stabilising the matching electrons), although two of the 7p energy levels are stabilised more often than the other four.
  • The inert pair effect is responsible for the stability of the 7s electrons, whereas subshell splitting is responsible for the "tearing" of the 7p subshell towards less and more stable portions.
  • Some probable properties are: It should experience inert pair effect like Thallium and hence +1oxidation state should be favoured, like Tl+, and consistent with this the first ionisation potential of Moscovium should be around 5.58 eV, continuing the trend towards lower ionisation potentials down the pnictogens.
  • Moscovium has one electron outside a quasi-closed shell configuration that can be delocalised in the metallic state. So, their melting and boiling points should be similar due to the similar strength of their metallic bonds.
  • Additionally, the predicted ionisation potential, ionic radius (1.5 Å for Mc+; 1.0 Å for Mc3+), and polarizability of Mc+ are expected to be more similar to Tl+.

Fundamental Data

Atomic Number


Atomic Mass

288 u

Electronegativity according to Pauling’s Scale

Yet to be determined


Yet to be determined

Melting Point

Yet to be determined

Boiling Point

Yet to be determined

Van Der Waals radius

Yet to be determined

Ionic Radius




Electronic Shell

[Rn] 5f14 6d10 7s2 7p3

First Ionisation Enthalpy

Yet to be determined.


In 2010, the Joint Institute for Nuclear Research 

Chemical Properties

  • The last participant in the Nitrogen family is likely to be Moscovium.
  • In the periodic table, it falls as the bulkiest member of group 15, just below bismuth.
  • Moscovium is expected to be very similar in properties when compared to its preceding element, bismuth. This property was not seen in the previous two groups when the 7th period is considered.
  • Every member of this group is well-known for exhibiting the group oxidation state of +5, even with varying stability.
  • Moscovium would be a reactive metal and would normally reduce the Mc+/Mc pair by −1.5 V.
  • The chemistry of moscovium in aqueous solution should essentially be that of the Mc+ and Mc3+ ions. The former should be easily hydrolysed and not be easily complexed with halides, cyanide, and ammonia.
  • Moscovium(I) hydroxide (McOH), carbonate (Mc2CO3), oxalate (Mc2C2O4), and fluoride (McF) should be soluble in water; the sulfide (Mc2S) should be insoluble; and the chloride (McCl), bromide (McBr), iodide ((McI), and thiocyanate (McSCN) should be only slightly soluble, so that adding excess hydrochloric acid would not noticeably affect the solubility of moscovium(I) chloride.
  • Moscovine (McH3) is expected to have a trigonal pyramidal molecular geometry, similar to its lighter homologues ammonia, phosphine, arsine, stibine, and bismuthine.


  • Ununpentium particles are generated in such small quantities that they are solely used for scientific research and study.
  • It is also utilised in the production of metal Ununtrium or Nihonium.

There is no biological use for it. As the metal is thought to be highly radioactive, it is believed to be extremely dangerous in nature.

Practice Problems

Q 1. What is the IUPAC nomenclature of an element with the atomic number 115?

 a. Ununpentium
b. Ununbium
c. Unnilbium
d. Unnilpentium

Answer: In the IUPAC nomenclature of elements with atomic number greater than 100, the code for 1 is un, for 5 is pent, and at the end, we add "ium". Therefore, when Z= 115, its IUPAC name is Ununpentium. 

So, option A is the correct answer.

Q 2. The new name for Ununpentium, accepted by international bodies is?

 a. Tenesium
b. Americium
c. Moscovium
d. Nihonium

Answer: Ununpentium was synthesised in Moscow in collaboration with Russian scientists. So, to honour that, it was named Moscovium. 

So, option C) is the correct answer.

Q 3. To which period and group does Ununpentium belong?

 a. Period 5, Group 17
b. Period 7, Group 15
c. Period 8, Group 7
d. Period 17, Group 18

Answer:  The electronic configuration of Moscovium/Ununpentium is [Rn] 5f14 6d10 7s2 7p3. Hence, it belongs to period 7 and group 15. 

So, option B) is the correct answer.

Frequently Asked Questions - FAQ

Q 1. What is Moscovium used for?
Answer: Only a few moscovium atoms have ever been created, and they are only used in scientific experiments. Nihonium is synthesised from it. Moscovium is a radioactive, synthetic substance about which little is known. It is known as a metal and is expected at room temperature to be solid. It rapidly decays into other elements, such as nihonium.

Q 2. Is Moscovium toxic?
Answer: The only known cause of moscovium is nuclear weapons. Moscovium has never been found in nature, and it has no biological function. It is expected to be poisonous, owing to its radioactivity and the likelihood that biochemical reactions will displace other metals.

Q 3. What is the 116th element?
Answer: Livermorium is a synthetic chemical element with the symbol Lv and an atomic number of 116. It is a highly radioactive element that was created in the laboratory and not found in nature.

Q 4. What is the most expensive metal on earth?
Answer: Palladium is the most expensive of the four main precious metals, with gold, silver, and platinum being the others. It is rarer than platinum, which is used in greater quantities in catalytic converters.

Related Topics


Alkali Metals

Sodium Hydroxide

Sodium Carbonate

Thermal Stability

Calcium Carbonate

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