U or Uranium is an actinide heavy metal and weakly radioactive in nature. Let us discuss uranium in this article.
Uranium appears silvery grey in color and is the third member of actinide series. Uranium has the highest atomic weight of primordially occurring elements. Its density is almost 70% of lead and slightly lower than gold and tungsten, so it is of hard metal. Uranium is extracted from the mineral Uraninite.
In this article, we will discuss the position of uranium in the periodic table, melting as well as boiling point, oxidation state, ionization energy, allotrope, and many other related facts.
1. Uranium symbol
The atomic symbol of Uranium is “U” which is abbreviated from the English alphabet.
2. Uranium group in the periodic table
The group of Uranium in the periodic table is unknown because all actinide elements are present in between the 3rd and 4th groups of the periodic table. The poor shielding effect of 5f is responsible for the actinide contraction.
3. Uranium period in the periodic table
Uranium belongs to period 7 in the periodic table because it has more than 86 electrons in the valence shell.
4. Uranium block in the periodic table
Uranium is an f-block element because the valence electrons are present in the f orbital. U also has s, p, and d orbitals but the outermost electrons are present in the 5f orbital according to the Aufbau principle.
5. Uranium atomic number
The atomic number of Uranium is 92, which means it has 92 protons because the number of protons is always equal to the number of electrons.
6. Uranium atomic Weight
The atomic weight of Uranium is 238 on the 12C scale which means the weight of Uranium is the 238/12th part of the weight of the carbon element.
7. Uranium Electronegativity according to Pauling
The electronegativity of Uranium is 1.38 according to the Pauling scale. U is rare earth metal so it possesses an electropositive character which reflects in its electronegativity value.
8. Uranium atomic Density
The atomic density of Uranium is 19 g/cm3 which can be calculated by dividing the mass of Uranium by its volume.
9. Uranium melting point
The melting point of Uranium is 11320C or 1405K temperature because it is a heavy metal so the van der Waal’s force of attraction in the crystal form is high.
10. Uranium boiling point
The boiling point of Uranium is 41310C or 4404K because it is a heavier metal and metal needs more energy to boil off to gain the same pressure as the atmosphere.
11. Uranium Van der Waals radius
The van der Waal’s radius of Uranium is 230 pm because it has 7s orbital which has more spatial distribution but also has relativistic contraction and 5f orbital so it has a poor screening effect. So, the nucleus attraction force for the outermost orbital increases, and this decreases the radius.
12. Uranium ionic radius
The ionic radius of Uranium is 230 pm which is the same as the covalent radius because for Uranium the cation and anion are the same and it is not an ionic molecule. Rather, it forms by the covalent interaction between two Uranium atoms.
13. Uranium 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 Uranium.
Uranium has 36 isotopes depending on the neutral numbers which are –
- 214U
- 215U
- 216U
- 216mU
- 217U
- 218U
- 219U
- 220U
- 221U
- 222U
- 223U
- 224U
- 225U
- 226U
- 227U
- 228U
- 229U
- 230U
- 231U
- 232U
- 233U
- 234U
- 235U
- 236U
- 236m1U
- 236m2U
- 237U
- 238U
- 239U
- 239m1U
- 239m2U
- 240U
- 241U
- 242U
Only 6 isotopes of Uranium are stable which are discussed below
| Isotope | Natural Abundance |
Half-life | Emitting particles |
No. of Neutron |
| 232U | Synthetic | 68.9 y | SF, α | 140 |
| 233U | trace | 1.59*105 y | SF, α | 141 |
| 234U | 0.005% | 2.45*105 y | SF, α | 142 |
| 235U | 0.720% | 7.04*108 y | SF, α | 143 |
| 236U | trace | 2.342*107 y | SF, α | 144 |
| 238U | 99.274% | 4.468*109 y | SF, α, ββ | 146 |
14. Uranium 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 Uranium.
The electronic shell distribution of Uranium is 2 8 18 32 21 9 2 because it has s, p, d, and f orbitals around the nucleus. Since it has more than 86 electrons and to arrange 92 electrons it needs 1, 2, 3, 4, 5, 6, and 7th orbitals.
15. Uranium electron configurations
The electronic configuration of Uranium is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f3 6s2 6p6 6d3 7s2 because it has 92 electrons and those electrons should be placed to the nearest orbital of the nucleus s, p, d, and f orbitals and denoted as [Rn]5f36d17s2.
16. Uranium energy of first ionization
The first ionization value for Uranium is 597.6 KJ/mol because the electron is removed from the 7s orbital which is subject to relativistic contraction.
17. Uranium energy of second ionization
The 2nd ionization energy of Uranium is 1420 KJ/mol because, in the 2nd ionization, electrons are removed from the same 7s orbital. Upon 2nd ionization, U does not lose its stability but the 2nd electron is removed from the excited state so it required much energy.
18. Uranium energy of third ionization
The third ionization energy for Uranium is 1900 KJ/mol because the third ionization occurs from 6d which has a poor shielding effect so the energy required is very high.
19. Uranium oxidation states
U shows a variable oxidation state from -1 to +6. Those oxidation states are stable for uranium due to the availability of electrons in respective orbitals.
20. Uranium CAS number
The CAS number of the Uranium molecule is 7440-61-1, which is given by the chemical abstracts service.
21. Uranium Chem Spider ID
The Chem Spider ID for Uranium is 55606. By using this number, we can evaluate all the chemical data related to the Uranium atom.
22. Uranium allotropic forms
Allotropes are elements or molecules with similar chemical properties but different physical properties. Let us discuss the allotropic form of Uranium.
Uranium has three allotropic forms and they are –
- α-Uranium – which is orthorhombic in structure and stable at 940K
- β-Uranium – adopts a tetragonal lattice structure and exists at 940 to 1047 K.
- γ-Uranium – it has a body-centered cubic structure and is stable at above 1047 K and it is the more ductile and malleable state of uranium.
23. Uranium chemical classification
Uranium is classified into the following categories:
- U is the rare earth element
- U is actinide heavy metal
- U is a weakly radioactive element
- U is an amphoteric oxide at +6 oxidation state.
24. Uranium state at room temperature
Uranium exists in a solid at room temperature because it exists in the orthorhombic lattice structure.
25. Is Uranium paramagnetic?
Paramagnetism is the tendency of magnetization in the direction of the magnetic field. Let us see whether Uranium is paramagnetic or not.
Uranium is paramagnetic because it has three unpaired electrons in its 5f and due to heavier elements, the magnetic moment not only depends on spin-only value but also there is some orbital contribution present.
Conclusion
Uranium is a weakly radioactive element so it can be used in nuclear reactors and making different or higher-order radioactive isotopes. Due to the variable oxidation state, only uranium can form various classes of organometallic compounds with CFT values.
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Hi……I am Biswarup Chandra Dey, I have completed my Master’s in Chemistry from the Central University of Punjab. My area of specialization is Inorganic Chemistry. Chemistry is not all about reading line by line and memorizing, it is a concept to understand in an easy way and here I am sharing with you the concept about chemistry which I learn because knowledge is worth to share it.