Roentgenium

Roentgenium, ₁₁₁Rg

Roentgenium
Pronunciation	/rʌntˈɡɛniəm/ ⓘ (runt-GHEN-ee-əm) /rɛntˈɡɛniəm/ (rent-GHEN-ee-əm)
Mass number	[282] (unconfirmed: 286)
Roentgenium in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Au ↑ Rg ↓ (Uhp) darmstadtium ← roentgenium → copernicium
Atomic number (Z)	111
Group	group 11
Period	period 7
Block	d-block
Electron configuration	[Rn] 5f14 6d9 7s2 (predicted)[1][2]
Electrons per shell	2, 8, 18, 32, 32, 17, 2 (predicted)
Physical properties
Phase at STP	solid (predicted)[3]
Density (near r.t.)	22–24 g/cm3 (predicted)[4][5]
Atomic properties
Oxidation states	(−1), (+1), (+3), (+5), (+7) (predicted)[2][6][7]
Ionization energies	1st: 1020 kJ/mol 2nd: 2070 kJ/mol 3rd: 3080 kJ/mol (more) (all estimated)[2]
Atomic radius	empirical: 138 pm (predicted)[2][6]
Covalent radius	121 pm (estimated)[8]
Other properties
Natural occurrence	synthetic
Crystal structure	​body-centered cubic (bcc) (predicted)[3]
CAS Number	54386-24-2
History
Naming	after Wilhelm Röntgen
Discovery	Gesellschaft für Schwerionenforschung (1994)
Isotopes of roentgenium v e
Main isotopes[9] Decay abun­dance half-life (t1/2) mode pro­duct 279Rg synth 0.09 s[10] α87% 275Mt SF13% – 280Rg synth 3.9 s α 276Mt 281Rg synth 11 s[11] SF86% – α14% 277Mt 282Rg synth 2 min[12] α 278Mt 283Rg synth 5.1 min?[13] SF – 286Rg synth 10.7 min?[14] α 282Mt
Category: Roentgenium view talk edit | references

Roentgenium (German: [ʁœntˈɡeːni̯ʊm] ^ⓘ) is a synthetic chemical element; it has symbol Rg and atomic number 111. It is extremely radioactive and can only be created in a laboratory. The most stable known isotope, roentgenium-282, has a half-life of 120 seconds, although the unconfirmed roentgenium-286 may have a longer half-life of about 10.7 minutes. Roentgenium was first created in 1994 by the GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany. It is named after the physicist Wilhelm Röntgen (also spelled Roentgen), who discovered X-rays. Only a few roentgenium atoms have ever been synthesized, and they have no practical application.

In the periodic table, it is a d-block transactinide element. It is a member of the 7th period and is placed in the group 11 elements, although no chemical experiments have been carried out to confirm that it behaves as the heavier homologue to gold in group 11 as the ninth member of the 6d series of transition metals. Roentgenium is calculated to have similar properties to its lighter homologues, copper, silver, and gold, although it may show some differences from them. Roentgenium is thought to be a solid at room temperature and to have a metallic appearance in its regular state.