Ni2+ Electron Configuration(Explained for Beginners)

In this article, we should discuss the Ni2+ electron configuration, Ni²⁺ magnetic behavior, Ni²⁺ complex formation, and detailed fact.

The position of Ni in the periodic table is the 4^th period and group 10^th element. It is a d block element and transition metal element (partially or fully filled d electrons in the ground state ) with atomic number 28. Ni²⁺ is a dication of Ni having 26 electrons.  Ni has fully filled d electrons but Ni² has 8 d electrons. It is 3d series.

Some facts about Ni²⁺

Ni2+ electron configuration is 1s²2s²2p⁶3s²3p⁶3d⁸4s². The atomic radious of Ni²⁺70 pm. Ni²⁺ having  fcc (face centre cubic ) crystal structure.

From the electronic configuration, it is evident that Ni²⁺ has 8 d electrons, so it is often referred to as a 3d⁸ electron element. So Ni²⁺ has more d electrons so it has a high affinity to bing Ï€- acidic ligand in organometallic chemistry like PPh₃, CO, CN, etc.

Ni is a moderately electropositive transition element, so Ni²⁺  is formed due to the loss of two electrons and the standard electrode potential for this process is positive.

Ni – 2e⁻ = Ni²⁺, ΔE⁰ = +0.24V

Ni2+ electron configuration

 As discussed, earlier Ni²⁺ belongs to the 3d block element so it has 8  d electrons in the outermost shell. The total number of electrons in Ni²⁺ is 26. They are distributed as follows,

1s²2s²2p⁶3s²3p⁶3d⁸4s²

From the above Ni2+ electron configuration it is shown that 8 electrons are present in the 3d shell and 2 electrons are present in the 4s shell. But due to exchange energy and according to the Aufbau principle electrons first filled in the 4s orbital and donated from the 3d orbital. So, the valence shell is a 3d shell for transition elements. So, the octet of Ni²⁺ is not completed as two electrons missing from its valence shell, so it is more reactive than Ni and participates in many reactions.

How many electrons does Ni2+ have ?

The number of electrons in Ni²⁺ is 26.

1s orbital has two electrons, 2s and 2p have 8 electrons, 3s,3p, and 3d have 16 electrons and 4s orbital has the rest of two electrons. Individually 3d orbital has 8 electrons, so Ni²⁺ has 8 d electrons which are valence shell electrons and participate in different reactions.

How many protons are in Ni2+ ion ?

The number of proton and electrons are the same for every element.

For Ni, the total number of electrons is 28 (1s²2s²2p⁶3s²3p⁶3d¹⁰4s² ,ni2+ electron configuration), so the number of protons in Ni is also 28 as the Ni is neutral and proton and electrons are cancel out their charge. But in Ni²⁺ there is a shortage of two electrons but the protons are reminded the same so the charge over Ni²⁺ is +2 for two extra protons cause the electrons are 26 but the number of protons is still 28.

Ni²⁺ molar mass

The Molar mas of Ni²⁺ is 58.69 g/mol.

We know the molar mass is equal to the molecular mass of that element divided by its own number of substances. For Ni, the molecular mass is 58.69 g. The number of substances is 1 here. So, the molar mass of Ni is 58.69 g/mol. For Ni²⁺ the molecular weight is as same as Ni, cause Ni²⁺ is only the dication of Ni, so no change in mass and there is no effect in the number of cations and anions in molar mass. So, the molar mass of Ni²⁺ equal to Ni is 58.69 g/mol.

CFT of Ni²⁺

CFT or Crystal Filed Theory is only applicable for transition or inner transition elements. Here we consider only the outermost electrons that is d electrons only.

For CFT we only consider the outermost shell that is only d electrons. First of all, the electrons in d electrons are distributed in five subsets and then arrange in order to their energy. The electrons are filled according to Hund’s rule and Pauling’s exclusion principle. From Ni2+ electron configuration,

The electrons in the subset are divided according to their energy to t_2g and e_g (in the octahedral field). T_2g set contains d_xy, d_yz, d_zx, and e_g set contains d_x²–_y² and d_z². From the above diagram for Ni²⁺ ion six electrons are present in the t_2g set of orbital and two electrons are present in the e_g set of the orbital.

Now we calculate the CFSE (Crystal filed stabilization energy), for Ni²⁺ ion in an octahedral field.

The energy of each orbital is and the energy of each orbital is .

Therefore, the total CFSE for Ni²⁺ is .

From this CFT, we can easily calculate the number of unpaired electrons, and the magnetic behavior of Ni²⁺.

Number of unpaired electrons in Ni²⁺

The number of unpaired electrons for Ni²⁺ is two.

From the box diagram and Ni2+ electron configuration, it is evident that among 8 electrons of Ni²⁺ in d orbital, six electrons are paired in d_xy, d_yz, d_zx, orbitals, and two electrons remain in unpaired form in d_x²–_y² and d_z²orbital. So, the number of unpaired electrons in Ni²⁺  is two. The filling of electrons according to Hund’s rule, that is first each subset filled via single electrons only, after filling all the subset then other electrons come to pair up.

Magnetic behavior of Ni²⁺

The magnetic behavior of any element is dependent on the number of unpaired electrons present.

From the box diagram as well as Ni2+ electron configuration, it is shown that Ni²⁺ has two unpaired electrons. So, it is paramagnetic in nature.

The magnitude of the magnetic moment can be calculated by the formula, [n(n+2)]^1/2, where n is the number of unpaired electrons. For Ni²⁺ the number of unpaired electrons is 2.

So, the magnetic moment of Ni²⁺ is [(2(2+2)]^1/2 = 2.82 B.M.

Ni(II) complex is paramagnetic but Ni(O) complex is diamagnetic. why?

From Ni2+ electron configuration, in Ni(II) complex the oxidation number of Ni is +2, 8 electrons present in the d orbital. Where in Ni(0) complex, Ni is a zerovalent state, and hence it is the d¹⁰ system that is d orbitals are fully filled.

Hence the complex of Ni(0) has no unpaired electrons unlike the case of the Ni(II) complex and hence it is diamagnetic in nature.

Biswarup Chandra Dey

Hi……I am Biswarup Chandra Dey, I have completed my Master’s in Chemistry from the Central University of Punjab. My area of specialization is Inorganic Chemistry. Chemistry is not all about reading line by line and memorizing, it is a concept to understand in an easy way and here I am sharing with you the concept about chemistry which I learn because knowledge is worth to share it.