Berkelium Properties (25 Facts You Should Know)

Bk or berkelium is transuranic and the 9th member of the actinide series. Let us discuss the berkelium in this article.

Being transuranic element berkelium is a radioactive metal element belonging to the actinide series. It is super heavy metal as it has higher atomic density and atomic weight. It is soft and silvery white metal and it is relatively safe to handle because it emits lower-energy electrons.

In the following part of the article, we can learn about the position of the berkelium in the periodic table along with its properties.

1. Berkelium symbol

Berkelium is represented as “Bk” because the first letter and first two letters are being used for other elements.

Berkelium Atomic Symbol

2. Berkelium group in the periodic table

Berkelium has no specified group in the periodic table, it lies between the 3rd and 4th groups along with other actinides, due to actinide contraction.

3. Berkelium period in the periodic table

The period of berkelium is 7th because, It has 97 electrons.

87-118 or
Period of Berkelium

4. Berkelium block in the periodic table

Bk lies in the f block as its azimuthal quantum number is 3, and also it has the last electrons present in the 5f orbital, which is its valence orbital also.

5. Berkelium atomic number

The total electrons are 97 for the berkelium which is its atomic number or z value which means it has the same number of protons also in the nucleus.

6. Berkelium atomic Weight

As per the 12C scale, the atomic weight of Berkelium is 247.342 which means it is 247.342/12th of the weight of the atomic weight of carbon itself.

7. Berkelium Electronegativity according to Pauling

As berkelium is a metal element so it has 1.57 electronegativity as per the Pauling scale and can easily form mono or bi cation.

8. Berkelium atomic Density

Berkelium has a 14.4 g/cm3 atomic density which can reflect that it is a super heavy element, with higher density.

9. Berkelium melting point

The melting point of berkelium is 984.80C or 1257.8K because it has double hexagonal close-packed in crystal form in the solid state.

10. Berkelium boiling point

The boiling point of berkelium is quite high 26270C or 2900K because when it is in the liquid form then there will be van der Waal’s attraction and to break the force need higher energy so its boiling energy will be high.

11. Berkelium Van der Waals radius

The van der Waal’s radius of Berkelium is 200 pm because it has 7s orbital along with 6d and 5f orbital which have poor shielding effects and relativistic contraction respectively.

12. Berkelium ionic radius

The ionic radius of Berkelium is 200 pm.

13. Berkelium 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 Berkelium.

Based on neutrons, number neptunium has 23 isotopes –

  • 233Bk
  • 234Bk
  • 236Bk
  • 238Bk
  • 239Bk
  • 240Bk
  • 241Bk
  • 242Bk
  • 242mBk
  • 243Bk
  • 244Bk
  • 245Bk
  • 246Bk
  • 247Bk
  • 248Bk
  • 248mBk
  • 249Bk
  • 250Bk
  • 250m1Bk
  • 250m2Bk
  • 251Bk
  • 252Bk
  • 253Bk

Here only stable isotopes are discussed below –

No. of
245BkSynthetic4.94 dα, €,148
246BkSynthetic1.8 dα, €149
247BkSynthetic1380 yα150
248BkSynthetic300 yα151
249BkSynthetic330 dα, SF, β152
Isotopes of Berkelium

14. Berkelium 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 Berkelium.

Berkelium has 2 8 18 32 27 8 2 sets of the electronic shell of 97 electrons and those electrons can be arranged around the nucleus in the s, p, d, and f orbital in this way by their principle as well as magnetic quantum number.

15. Berkelium electron configurations

The berkelium electronic configuration is [Rn]5f97s2 or 1s2  2s2  2p6  3s2  3p 3d10  4s2  4p6  4d10  4f14  5s2  5p6  5d10 5f7 6s2 6p6 7s2, which is slightly different from other actinides as it lacks 6d orbital for stability and it has also 1 to 7th principle quantum number.

16. Berkelium energy of first ionization

Berkelium has 601 KJ/mol as its first I.E. which occurs from 7s orbital and due to relativistic contraction the energy will be high.

17. Berkelium energy of second ionization

The second ionization energy is 1186 KJ/mol of Bk which is almost double of its first one because it occurs from a +1 excited state and from the same 7s orbital which has relativistic contraction and nucleus attraction will be higher.

18. Berkelium energy of third ionization

The third ionization energy for Berkelium is so high 2026 KJ/mol and the reasons are –

  • The third electron is removed from the 5f orbital as it lacks a 6d orbital and 5f is closer to the nucleus.
  • 5f shields the nucleus very poorly and for this reason, nuclear attraction force will be high
  • Third ionization occurs from the +2 excited state of a system.

19. Berkelium oxidation states

Berkelium can show variable oxidation states from +2 to +5  due to the absence of 6d orbital, but +3 is the most stable oxidation state of the bk like other actinides.

20. Berkelium CAS number

As per the chemical abstracts service, the CAS number of the Berkelium molecule is 7440-40-6.

21. Berkelium Chem Spider ID

22409 is the chem spider id for the Berkelium.

22. Berkelium allotropic forms

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

Due to its highly radioactive nature, no allotropic forms of Berkelium is found.

23. Berkelium chemical classification

Berkelium can be classified into the following classes –

  1. Berkelium is one of the transuranic super heavy element
  2. Berkelium is the highly radioactive metal
  3. Berkelium is also rare earth metal like another actinide
  4. Berkelium is the synthetic actinide.

24. Berkelium state at room temperature

Due to the double hexagonal close-packed lattice present in the crystal form of Berkelium, it exists as a solid at room temperature.

25. Is Berkelium paramagnetic?

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

Berkelium has five unpaired electrons among 9 electrons of 5f orbital so it is paramagnetic in nature, but the original magnetic values are calculated by the spin as well as orbital contribution.


Due to its highly radioactive nature and synthetically prepared actinides, Berkelium has no commercial use but it can be used to produce other radioactive element isotopes,

Scroll to Top