Cr³⁺ ion
[Ar] 3d³. 3 unpaired electrons, paramagnetic.
Element or ion
Type a symbol, a name or an atomic number, add a charge such as Fe3+ or Cl-, or tap an element in the table. Orbitals fill from m = −l up, spin +½ first.
Cr3+Chromium ion, 21 electrons
[Ar] 3d3
In full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d³. Cr loses 4s¹ then 3d²
Cr loses 4s¹ then 3d²
- Blockd block
- Period4
- Group6
- Outer shell11
- Unpaired3
- MagneticPara
Last electron 3d
- n3shell
- l2d subshell
- m0orbital
- s+½spin up
Step by step
- Chromium has 24 electrons: [Ar] 3d⁵ 4s¹.
- The ion has 3 fewer, 21 electrons. Remove them from the highest n first.
- Cr loses 4s¹ then 3d².
- Cr³⁺ ion: [Ar] 3d³, in full 1s² 2s² 2p⁶ 3s² 3p⁶ 3d³.
Cr³⁺ ion: the numbers
| Atomic number | 24 |
|---|---|
| Electrons | 21 |
| Period | 4 |
| Group | 6 |
| Block | d block |
| Electrons in the outer shell | 11 |
| Unpaired electrons | 3 |
| Magnetic | paramagnetic |
| Last electron | 3d: n = 3, l = 2, m = 0, s = +1/2 |
Cr³⁺ ion: quick answers
What is the electronic configuration of Cr³⁺?
Cr³⁺ has 21 electrons: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d³, or [Ar] 3d³. Cr loses 4s¹ then 3d².
How many unpaired electrons are there in Cr³⁺?
Cr³⁺ has 3 unpaired electrons, so it is paramagnetic.
Why does Cr lose its outer electrons first?
Electrons leave from the highest n first. The 4s level fills before 3d, but once 3d holds electrons the 4s electrons are the outermost, so they are lost first.