Curium Electron Configuration
★ Exception to the Aufbau order. Predicted 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f8 6s2 6p6 7s2; measured 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 5f7 6d1 7s2.
Orbital diagram
- Valence electrons
- 3
- Unpaired electrons
- 8
- Block
- f-block
- Magnetism (atom)
- paramagnetic
Electrons per shell
| K (n = 1) | 2 |
|---|---|
| L (n = 2) | 8 |
| M (n = 3) | 18 |
| N (n = 4) | 32 |
| O (n = 5) | 25 |
| P (n = 6) | 9 |
| Q (n = 7) | 2 |
Curium ion configurations
| Ion | Electrons | Configuration |
|---|---|---|
| Cm3+ | 93 | [Rn] 5f7 |
How to write it
Place 96 electrons into subshells in the Aufbau order (1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p), filling s with 2, p with 6, d with 10 and f with 14. Curium sits in period 7, in the f-block, so its last electron enters a f subshell. Replacing the inner electrons with the previous noble gas gives the shorthand [Rn] 5f7 6d1 7s2.
Try curium and its ions in the calculator, or see the full curium data sheet.
Curium electron configuration FAQ
What is the electron configuration of curium?
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 5f⁷ 6d¹ 7s². Shorthand (noble gas) notation: [Rn] 5f⁷ 6d¹ 7s².
What is the noble gas configuration of curium?
[Rn] 5f⁷ 6d¹ 7s². The bracket stands for the Rn core electrons.
Why is curium’s electron configuration an exception?
The simple filling (Aufbau) order predicts 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f⁸ 6s² 6p⁶ 7s², but the measured ground state is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 5f⁷ 6d¹ 7s². Shifting an electron gives a half-filled or filled subshell, which has extra exchange stability.
How many valence electrons does curium have?
3 (2 outer s + 1 d electrons; 2 in the outermost shell).
How many unpaired electrons does curium have?
8 in the ground state, following Hund’s rule. An atom with unpaired electrons is paramagnetic.
What is the electron configuration of Cm3+?
[Rn] 5f⁷ (93 electrons).