Californium (Cf): Bohr Model, Protons, Neutrons & Electrons
Californium is element number 98, an actinide in the f-block (the actinide row drawn below the table), period 7. Its atom has 98 protons, 153 neutrons and 98 electrons arranged in 7 shells: 2, 8, 18, 32, 28, 8, 2.
- 98 protons
- 153 neutrons
- 98 electrons
Protons, neutrons and electrons in californium
Le atomic number of californium is 98, so every californium atom has 98 protons. A neutral atom has the same number of electrons, 98. The number of neutrons depends on the isotope: neutrons = mass number − atomic number. For californium-251, that is 251 − 98 = 153 neutrons. Every isotope of californium is radioactive; 251 is the mass number of its most stable one.
How to draw the Bohr model of californium
- Draw the nucleus and write 98 p⁺ et 153 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 28 electrons on it.
- Draw the sixth shell and put 8 electrons on it.
- Draw the seventh shell and put 2 electrons on it.
- Check: 2 + 8 + 18 + 32 + 28 + 8 + 2 = 98 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, 28, 8, 2) is the one to draw.
Electron configuration
The electron configuration of californium is [Rn] 7s² 5f¹⁰. As an actinide it fills an inner f-subshell, and its common ion is Cf³⁺.
Key facts about californium
| Symbol | Cf |
|---|---|
| Atomic number | 98 |
| Relative atomic mass | [251] |
| Group · period · block | f-block · period 7 |
| Type | Actinide |
| State at 25 °C | solid |
| Couches électroniques | 2, 8, 18, 32, 28, 8, 2 |
| Electron configuration | [Rn] 7s² 5f¹⁰ |
| Électrons de valence | varies (outer shell: 2) |
| Common ion | Cf³⁺ |
| Electronegativity (Pauling) | 1.30 |
| First ionisation energy | 6.28 eV (606 kJ/mol) |
| Atomic radius (empirical) | — |
Où californium sits on the periodic table
Foire aux questions
How many protons, neutrons and electrons does californium have?
Californium has 98 protons and 98 electrons (atomic number 98). Its most common isotope, californium-251, has 251 − 98 = 153 neutrons.
What is the electron configuration of californium?
[Rn] 7s² 5f¹⁰. In shells that is 2, 8, 18, 32, 28, 8, 2.
How many valence electrons does californium have?
Californium is an actinide, so its valence electrons are spread over two shells; its outermost shell holds 2.
Where is californium 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.
