Uranio (U): Bohr Model, Protons, Neutrons & Electrons
Uranio is element number 92, an actinide in the f-block (the actinide row drawn below the table), period 7. Its atom has 92 protons, 146 neutrons and 92 electrons arranged in 7 shells: 2, 8, 18, 32, 21, 9, 2.
- 92 protons
- 146 neutrons
- 92 electrons
Protons, neutrons and electrons in uranium
El atomic number of uranium is 92, so every uranium atom has 92 protons. A neutral atom has the same number of electrons, 92. The number of neutrons depends on the isotope: neutrons = mass number − atomic number. For uranium-238, that is 238 − 92 = 146 neutrons. Every isotope of uranium is radioactive; 238 is the mass number of its most stable one.
How to draw the Bohr model of uranium
- Draw the nucleus and write 92 p⁺ y 146 n⁰ inside it.
- Draw the first shell and put 2 electrons on it (the first shell holds at most 2).
- Draw the second shell and put 8 electrons on it.
- Draw the third shell and put 18 electrons on it.
- Draw the fourth shell and put 32 electrons on it.
- Draw the fifth shell and put 21 electrons on it.
- Draw the sixth shell and put 9 electrons on it.
- Draw the seventh shell and put 2 electrons on it.
- Check: 2 + 8 + 18 + 32 + 21 + 9 + 2 = 92 electrons, the same as the number of protons.
From potassium onwards the shells don’t simply fill as 2, 8, 8: the fourth shell starts before the third is full, so the real arrangement above (2, 8, 18, 32, 21, 9, 2) is the one to draw.
Electron configuration
The electron configuration of uranium is [Rn] 7s² 5f³ 6d¹. As an actinide it fills an inner f-subshell, and its common ion is U⁴⁺.
Key facts about uranium
| Symbol | U |
|---|---|
| Atomic number | 92 |
| Relative atomic mass | 238.03 |
| Group · period · block | f-block · period 7 |
| Tipo | Actínido |
| State at 25 °C | solid |
| Capas electrónicas | 2, 8, 18, 32, 21, 9, 2 |
| Electron configuration | [Rn] 7s² 5f³ 6d¹ |
| Electrones de valencia | varies (outer shell: 2) |
| Common ion | U⁴⁺ |
| Electronegativity (Pauling) | 1.38 |
| First ionisation energy | 6.19 eV (597 kJ/mol) |
| Atomic radius (empirical) | 175 pm |
¿Dónde uranium sits on the periodic table
Preguntas frecuentes
How many protons, neutrons and electrons does uranium have?
Uranium has 92 protons and 92 electrons (atomic number 92). Its most common isotope, uranium-238, has 238 − 92 = 146 neutrons.
What is the electron configuration of uranium?
[Rn] 7s² 5f³ 6d¹. In shells that is 2, 8, 18, 32, 21, 9, 2.
How many valence electrons does uranium have?
Uranium is an actinide, so its valence electrons are spread over two shells; its outermost shell holds 2.
Where is uranium on the periodic table?
In the f-block (the actinide row drawn below the table), period 7, in the f-block. It is an actinide.
