Numford
Ion configuration

Fe²⁺ ion

[Ar] 3d⁶. 4 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.

+2
H1He2Li3Be4B5C6N7O8F9Ne10Na11Mg12Al13Si14P15S16Cl17Ar18K19Ca20Sc21Ti22V23Cr24Mn25Fe26Co27Ni28Cu29Zn30Ga31Ge32As33Se34Br35Kr36Rb37Sr38Y39Zr40Nb41Mo42Tc43Ru44Rh45Pd46Ag47Cd48In49Sn50Sb51Te52I53Xe54Cs55Ba56Hf72Ta73W74Re75Os76Ir77Pt78Au79Hg80Tl81Pb82Bi83Po84At85Rn86

Fe2+Iron ion, 24 electrons

[Ar] 3d6

In full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁶. Fe loses 4s²

Fe loses 4s²

[Ar]3d4s (empty)
  • Blockd block
  • Period4
  • Group8
  • Outer shell14
  • Unpaired4
  • MagneticPara

Last electron 3d

  • n3shell
  • l2d subshell
  • m−2orbital
  • s−½spin down
Working

Step by step

  1. Iron has 26 electrons: [Ar] 3d⁶ 4s².
  2. The ion has 2 fewer, 24 electrons. Remove them from the highest n first.
  3. Fe loses 4s².
  4. Fe²⁺ ion: [Ar] 3d⁶, in full 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁶.
At a glance

Fe²⁺ ion: the numbers

Atomic number26
Electrons24
Period4
Group8
Blockd block
Electrons in the outer shell14
Unpaired electrons4
Magneticparamagnetic
Last electron3d: n = 3, l = 2, m = −2, s = −1/2
Questions

Fe²⁺ ion: quick answers

What is the electronic configuration of Fe²⁺?

Fe²⁺ has 24 electrons: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁶, or [Ar] 3d⁶. Fe loses 4s².

How many unpaired electrons are there in Fe²⁺?

Fe²⁺ has 4 unpaired electrons, so it is paramagnetic.

Why does Fe 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.

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