Roentgenium (Rg)
Roentgenium was officially named in 2004, more than a century after Röntgen discovered X-rays in 1895.
Roentgenium properties
- Atomic number
- 111
- Atomic mass
- 282 u
- Category
- Unknown properties
- Group
- 11
- Period
- 7
- Block
- d-block
- State at room temp.
- Unknown
- Density
- —
- Electron affinity
- —
- Radioactive
- Yes, no stable isotopes
- Discovered
- 1994
Roentgenium electron configuration
- Electron configuration
- [Rn] 5f14 6d9 7s2
- Full electron configuration
- 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d9 7s2
- Electron shells
- 2 · 8 · 18 · 32 · 32 · 17 · 2
The electron configuration of Roentgenium (Rg) is [Rn] 5f14 6d9 7s2. Its 111 electrons are arranged in shells as 2, 8, 18, 32, 32, 17, 2.
Protons, neutrons and electrons in Roentgenium
A neutral Roentgenium atom has 111 protons and 111 electrons. Most Roentgenium atoms have about 171 neutrons: the atomic mass rounded to 282, minus the atomic number 111.
Neutrons are approximate: atoms of the same element can have different numbers of neutrons (isotopes). Atomic number and mass
How many valence electrons does Roentgenium have?
2
Roentgenium has 2 valence electrons, counting the electrons in its outermost s subshell. Like most transition metals, it can also use d electrons in bonding.
Roentgenium orbital diagram
Each box is an orbital that holds up to two electrons with opposite spins (↑↓). The inner shells are the same as the noble gas in brackets. How to write electron configurations
Molar mass of Roentgenium
282 g/mol
One mole of Roentgenium atoms (6.022 × 10²³ atoms) has a mass of 282 grams. Use this value to convert between grams and moles.
Roentgenium facts
- Roentgenium was officially named in 2004, more than a century after Röntgen discovered X-rays in 1895.
- Before it was named, element 111 was known by the temporary systematic name unununium.
- Roentgenium (Rg) has atomic number 111. It was discovered in 1994.
Position in the periodic table
Roentgenium is element 111, in period 7 and group 11 of the periodic table, in the d-block.
Uses of Roentgenium
Roentgenium has no uses outside research because only a small number of atoms have ever been made, and they decay within seconds to minutes. Calculations suggest it would behave like gold, the element above it in group 11, but no chemical experiments have been carried out on it yet.
Who discovered Roentgenium?
Sigurd Hofmann's team at GSI in Darmstadt, Germany, first made roentgenium in 1994 by bombarding bismuth with nickel ions. It is named after Wilhelm Röntgen, who discovered X-rays.
Where does the name come from?
Roentgenium honors Wilhelm Conrad Röntgen, the German physicist who discovered X-rays in 1895 and received the first Nobel Prize in Physics in 1901. The element was first made in 1994 in Darmstadt.
Same group
Compare Roentgenium
FAQ
What is the electron configuration of Roentgenium?
The electron configuration of Roentgenium (Rg) is [Rn] 5f14 6d9 7s2. Its 111 electrons are arranged in shells as 2, 8, 18, 32, 32, 17, 2.
How many protons, neutrons and electrons does Roentgenium have?
A neutral Roentgenium atom has 111 protons and 111 electrons. Most Roentgenium atoms have about 171 neutrons: the atomic mass rounded to 282, minus the atomic number 111.
How many valence electrons does Roentgenium have?
Roentgenium has 2 valence electrons, counting the electrons in its outermost s subshell. Like most transition metals, it can also use d electrons in bonding.
What is the molar mass of Roentgenium?
The molar mass of Roentgenium is 282 g/mol. This is the same number as its atomic mass, 282 u.
Is Roentgenium a metal?
Roentgenium is a synthetic superheavy element, so too few atoms have been made to measure whether it behaves as a metal.
Is Roentgenium radioactive?
Yes. Roentgenium has no stable isotopes, so all of its atoms are radioactive and eventually decay into other elements.
Where is Roentgenium on the periodic table?
Roentgenium is element 111, in period 7 and group 11 of the periodic table, in the d-block.