Curio (Cm): Bohr Model, Protons, Neutrons & Electrons
Curio is element number 96, an actinide in the f-block (the actinide row drawn below the table), period 7. Its atom has 96 protons, 151 neutrons and 96 electrons arranged in 7 shells: 2, 8, 18, 32, 25, 9, 2.
- 96 protons
- 151 neutrons
- 96 electrons
Protons, neutrons and electrons in curium
El atomic number of curium is 96, so every curium atom has 96 protons. A neutral atom has the same number of electrons, 96. The number of neutrons depends on the isotope: neutrons = mass number − atomic number. For curium-247, that is 247 − 96 = 151 neutrons. Every isotope of curium is radioactive; 247 is the mass number of its most stable one.
How to draw the Bohr model of curium
- Draw the nucleus and write 96 p⁺ y 151 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 25 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 + 25 + 9 + 2 = 96 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, 25, 9, 2) is the one to draw.
Electron configuration
The electron configuration of curium is [Rn] 7s² 5f⁷ 6d¹. As an actinide it fills an inner f-subshell, and its common ion is Cm³⁺.
Key facts about curium
| Symbol | Cm |
|---|---|
| Atomic number | 96 |
| Relative atomic mass | [247] |
| Group · period · block | f-block · period 7 |
| Tipo | Actínido |
| State at 25 °C | solid |
| Capas electrónicas | 2, 8, 18, 32, 25, 9, 2 |
| Electron configuration | [Rn] 7s² 5f⁷ 6d¹ |
| Electrones de valencia | varies (outer shell: 2) |
| Common ion | Cm³⁺ |
| Electronegativity (Pauling) | 1.28 |
| First ionisation energy | 5.99 eV (578 kJ/mol) |
| Atomic radius (empirical) | — |
¿Dónde curium sits on the periodic table
Preguntas frecuentes
How many protons, neutrons and electrons does curium have?
Curium has 96 protons and 96 electrons (atomic number 96). Its most common isotope, curium-247, has 247 − 96 = 151 neutrons.
What is the electron configuration of curium?
[Rn] 7s² 5f⁷ 6d¹. In shells that is 2, 8, 18, 32, 25, 9, 2.
How many valence electrons does curium have?
Curium is an actinide, so its valence electrons are spread over two shells; its outermost shell holds 2.
Where is curium 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.
