Circonio (Zr): Bohr Model, Protons, Neutrons & Electrons
Circonio is element number 40, a transition metal in group 4, period 5. Its atom has 40 protons, 50 neutrons and 40 electrons arranged in 5 shells: 2, 8, 18, 10, 2.
- 40 protons
- 50 neutrons
- 40 electrons
Protons, neutrons and electrons in zirconium
El atomic number of zirconium is 40, so every zirconium atom has 40 protons. A neutral atom has the same number of electrons, 40. The number of neutrons depends on the isotope: neutrons = mass number − atomic number. For zirconium-90, that is 90 − 40 = 50 neutrons. Zirconium has 5 stable isotopes, with 50, 51, 52, 54, 56 neutrons.
How to draw the Bohr model of zirconium
- Draw the nucleus and write 40 p⁺ y 50 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 10 electrons on it.
- Draw the fifth shell and put 2 electrons on it.
- Check: 2 + 8 + 18 + 10 + 2 = 40 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, 10, 2) is the one to draw.
Electron configuration
The electron configuration of zirconium is [Kr] 5s² 4d². As a transition metal it fills an inner d-subshell, and its common ion is Zr⁴⁺.
Key facts about zirconium
| Symbol | Zr |
|---|---|
| Atomic number | 40 |
| Relative atomic mass | 91.224 |
| Group · period · block | group 4 · period 5 · d-block |
| Tipo | Metal de transición |
| State at 25 °C | solid |
| Capas electrónicas | 2, 8, 18, 10, 2 |
| Electron configuration | [Kr] 5s² 4d² |
| Electrones de valencia | varies (outer shell: 2) |
| Common ion | Zr⁴⁺ |
| Electronegativity (Pauling) | 1.33 |
| First ionisation energy | 6.63 eV (640 kJ/mol) |
| Atomic radius (empirical) | 155 pm |
¿Dónde zirconium sits on the periodic table
Preguntas frecuentes
How many protons, neutrons and electrons does zirconium have?
Zirconium has 40 protons and 40 electrons (atomic number 40). Its most common isotope, zirconium-90, has 90 − 40 = 50 neutrons.
What is the electron configuration of zirconium?
[Kr] 5s² 4d². In shells that is 2, 8, 18, 10, 2.
How many valence electrons does zirconium have?
Zirconium is a transition metal, so its valence electrons are spread over two shells; its outermost shell holds 2.
Where is zirconium on the periodic table?
In group 4, period 5, in the d-block. It is a transition metal.
