Roentgenium Chemical Properties (21 Facts You Should Know)

Rg or Roentgenium is a transition element, extremely radioactive in nature, prepared in the laboratory. Let us explain Roentgenium in detail.

Rg is present in the same group as copper and silver and it is similar to gold in terms of properties. Its electronic configuration is quite different from its lighter congeners. It has filled 7s orbital but no 6d orbital, which may be the reason there is higher promotion energy present between 7s and 5d orbital.

Roentgenium is the first synthetically prepared element. Let us discuss the position of Rg in the periodic table, and some of the chemical and physical properties of Roentgenium, such as melting point, boiling point, atomic number, etc.

1. Roentgenium symbol

Symbols are used to express the element by using one or two letters of the English or Latin alphabet of the chemical name. Let us predict the atomic symbol of Roentgenium.

The atomic symbol of Roentgenium is “Rg” as the name start with the English alphabet R. But R represents the alkyl group in organic chemistry, so the abbreviation for Roentgenium is Rg, which is the most dominant letter of the term.

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Roentgenium Atomic Symbol

2. Roentgenium group in the periodic table

Vertical lines or columns of the periodic table are referred to as the respective group of the periodic table. Let us predict the group of Roentgenium in the periodic table.

The group of Roentgenium in the periodic table is 11. Due to the arrangement of electrons, Rg is placed in group 11 after gold. It behaves like a heavier homolog to gold. But in the modern periodic table, it is placed in group IB.

3. Roentgenium period in the periodic table

A horizontal line or row of the periodic table where every element is placed by its last principle quantum number is called a period. Let us predict the period of Roentgenium.

Roentgenium belongs to period 7 in the periodic table because it has more than 86 electrons in the valence shell. Up to period 6, there will be 86 elements that are well placed, so the remaining 25 electrons for the Rg get 7th period and 12th group along with actinide series.

4. Roentgenium block in the periodic table

The orbital where the element’s valence electrons are present is called the block of the periodic table. Let us predict the block of Roentgenium.

Roentgenium is a d-block element because the valence electrons are present in the d orbital. Rg also has a 7s orbital but the outermost electrons are present in the 6d orbital as per exchange energy and the Aufbau principle.

5. Roentgenium atomic number

The value of Z, known as the atomic number, is the total number of electrons. Let us find the atomic number of Roentgenium.

The atomic number of Roentgenium is 111, meaning it has 111 protons because the number of protons always equals the number of electrons. For this reason, they become neutral due to the neutralization of equal and opposite charges.

6. Roentgenium atomic Weight

The mass of the element is called weight which is measured concerning some standard value. Let us calculate the atomic weight of Roentgenium.

The atomic weight of Roentgenium on the 12C scale is 280 which means the weight of Roentgenium is the 65/12th part of the weight of the carbon element. The original atomic weight of Roentgenium is 282, it is because the atomic weight is the average weight of all the isotopes of the element.

7. Roentgenium Electronegativity according to Pauling

Pauling electronegativity is the power to attract any other element for that particular atom. Let us predict the electronegativity of Roentgenium.

The electronegativity of Roentgenium according to the Pauling scale is 0.7, which means it is more electropositive in nature and can attract electrons toward itself. It is a radioactive element so it has no data on the Pauling scale but based on francium, it can be calculated.

8. Roentgenium atomic Density

The number of atoms present per unit volume of any atom is called the atomic density of that respective element. Let us calculate the atomic density of Roentgenium.

The atomic density of Roentgenium is 28.7 g/cm3 which can be calculated by dividing the mass of Roentgenium with its volume. Atomic density means the number of atoms present per unit volume but atomic number is the number of electrons present in the valence and inner orbital.

  • Density is calculated by the formula, atomic density = atomic mass / atomic volume.
  • The atomic mass or weight of Roentgenium is 282 g
  • The volume of the Roentgenium molecule is 22.4 liter at STP as per Avogardo’s calculation
  • So, the atomic density of Roentgenium is, 282/ (9.15) = 28.7 g/cm3

9. Roentgenium Van der Waals radius

Van der Waal’s radius is the imaginary measurement between two atoms where they are not bound ionically or covalently. Let us find Van der Waal’s radius of Roentgenium.

The Van der Waal’s radius of Roentgenium molecule is 121 pm because Rg has 6s, 6d, 4f, and 7s orbital so it has a very poor screening effect. For this reason, the nucleus attraction force for the outermost orbital increases, and it decreases the radius.

  • Van der Waal’s radius is calculated by the mathematical formula considering the distance between two atoms, where atoms are spherical in shape.
  • Van der Waal’s radius is, Rv = dA-A / 2
  • Where Rstands for Van Waal’s radius of the molecule of spherical shape
  • dA-A is the distance between two adjacent spheres of the atomic molecule or the summation of a radius of two atoms.

10. Roentgenium ionic radius

The summation of cation and anion is called the ionic radius of the element. Let us find the ionic radius of Roentgenium.

The ionic radius of Roentgenium is 121 pm which is the same as the covalent radius because for Roentgenium the cation and anion are the same and it is not an ionic molecule. Rather, it forms by the covalent interaction between two Roentgenium atoms.

11. Roentgenium isotopes

Elements having the same number of electrons but different mass numbers are called isotopes of the original element. Let us discuss the isotopes of Roentgenium.

Roentgenium has 9 isotopes based on their neutron number which are listed below:

  • 272Rg
  • 274Rg
  • 278Rg
  • 279Rg
  • 280Rg
  • 281Rg
  • 282Rg
  • 283Rg
  • 286Rg

Stable isotopes are discussed in the below section among 9 isotopes of Roentgenium:

No. of
279RgSynthetic0.1 sα, SF168
280RgSynthetic4 sα169
281RgSynthetic17 sα, SF170
282RgSynthetic2 minα171
283RgSynthetic5.1 minSF172
286RgSynthetic10.7 minα175
Isotopes of Roentgenium

All the isotopes of the Roentgenium are synthetically prepared, as the mother element is radioactive so all the isotopes are radioactive and they can emit radioactive particles having very low stability.

12. Roentgenium electronic shell

The shell surrounding the nucleus as per principal quantum number and holding the electrons is called an electronic shell. Let us discuss the electronic shell of Roentgenium.

The electronic shell distribution of Roentgenium is 2 8 18 32 32 17 2 because it has s, p, d, and f orbitals around the nucleus. Since it has more than 86 electrons and to arrange 111 electrons, it needs 1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p, 5s, 5p, 5d, 4d, 6s, 6p, 4f, 6s, 6d, 5f, and 7s orbitals.

13. Roentgenium electron configurations

The electronic configuration is an arrangement of the electrons in available orbital by considering Hund’s rule. Let us discuss the electronic configuration of Roentgenium.

The electronic configuration of Roentgenium is 1s22s22p63s23p3d104s24p6 4d10 4f145s25p65d105f146s26p66d97s2 because it has 30 electrons and those electrons should be placed to the nearest orbital of the nucleus s, p, d, and f orbitals and for the 1st,2nd, 3rd, 4th,5th, 6th, and 7th orbitals.

  • Due to exchange energy, electrons enter first in 7s orbital then 6d.
  • Where the first number stands for the principal quantum number
  • The letter is for orbital and the suffix number is the number of electrons.
  • But many elements have more principal quantum numbers depending on the number of electrons.
  • Rn has 86 electrons, so the remaining electrons are present after the noble gas configuration.
  • So, it is denoted as [Rn]7s26d9.

14. Roentgenium energy of first ionization

First I.E. is the energy required for the removal of an electron from the valence orbital of its zero oxidation state. Let us predict the first ionization of Roentgenium.

The first ionization value for Rg is 1020 KJ/mol because the electron was removed from the filled 7s orbital. Due to lower shielding effects, the energy required to remove an electron from 7s is lesser than the other orbital of Rg. But it requires much more energy than expected, as 7s is subject to relativistic contraction.

15. Roentgenium energy of second ionization

The second I.E. is the energy required for the removal of one electron from the available orbital from the +1 oxidation state. Let us see the second I.E. of Roentgenium.

The 2nd ionization energy of Roentgenium is 2070 KJ/mol because in the 2nd ionization, electrons are removed from the half-filled 7s orbital. When an electron is removed from a half-filled orbital, it needs more energy and +1 is the stable state for Rg. Therefore, the 2nd ionization energy is very high than 1st.

16. Roentgenium energy of third ionization

Removal of the third electron from the outermost or pre-ultimate orbital of an element having a +2 oxidation state is the third I.E. Let us predict the third I.E. of Roentgenium.

The third ionization energy for Rg is 3080 KJ/mol because the third ionization occurs from the filled 3d orbital and the main two reasons are:

  1. Removing electrons from an inner orbital always require more energy than expected because stability is lost when electrons are removed from 6d orbital due to exchange energy.
  2. 6d orbital has a poor shielding effect, so it can shield the outer electron from the nucleus very poor. For this reason, the nucleus attraction force on the outermost electron will be increased and for removal of the electron, higher energy is required.

17. Roentgenium oxidation states

During bond formation, the charge that appears on the element is called the oxidation state. Let us predict the oxidation state of Roentgenium.

The stable oxidation state of Roentgenium is -1, +1, +3, +5, +7 because it has two electrons in the 7s orbital. When the electron is removed, Rg has one electron less from its filled 6d orbital and gives some extra stability due to zero exchange energy. So, accepting one electron gives a liquid noble configuration.

18. Roentgenium CAS number

CAS number or CAS registration for any element is used to identify the unique element. Let us know the CAS number of Roentgenium.

The CAS number of Roentgenium molecule is 54386-24-2, which is given by the chemical abstracts service.

19. Roentgenium allotropic forms

Allotropes are elements or molecules with similar chemical properties but different physical properties. Let us discuss the allotropic form of Roentgenium.

Roentgenium has no allotropic forms because it does not show catenation properties like carbon. Due to its radioactive nature, it always decays and changes to another element.

20. Roentgenium chemical classification

Based on the chemical reactivity and nature, the elements are classified into some special class. Let us know the chemical classification of Roentgenium.

Roentgenium is classified into the following categories:

  • Rg is a heavier transition metal element
  • Rg is a radioactive element
  • Rg is also classified as reactive based on the reaction tendency towards carbonyl.
  • Rg is more brittle and carries electricity as per electrical conductance.

21. Roentgenium state at room temperature

The physical state of an atom is the state at which an element exists at room temperature and standard pressure. Let us predict the state of Rg at room temperature.

Roentgenium exists in a solid state at room temperature because it has higher Van der Waal interaction. In the crystal form, it adopts body-centered cubic so the atoms exist very close to each other. The randomness of the atom is very high at room temperature.

The solid state of Roentgenium can be changed to liquid at a very low temperature, where the randomness will be decreased for Roentgenium atom.

22. Is Roentgenium paramagnetic?

Paramagnetism is the tendency of magnetization in the direction of the magnetic field. Let us see whether Roentgenium is paramagnetic or not.

Roentgenium is paramagnetic as it has one unpaired electron in its 6d orbital and the value is 1.732 B.M which is spin only value, but for the heavier element we consider orbital contribution also.


Rg is a heavier transition element that is radioactive and synthetically prepared. In the nuclear reactor it can be used for nucleus fission reaction. It is also used to form other elements or heavier isotopes.