Nickel

Nickel (Ni) is a transition metal with atomic number 28 and an atomic mass of 58.693. Its electron configuration is [Ar] 3d8 4s2.

Nickel key data

Symbol	Ni
Atomic number	28
Atomic mass (standard atomic weight)	58.693
Molar mass	58.693 g/mol
Protons	28
Neutrons (most abundant isotope, nickel-58)	30
Electrons (neutral atom)	28
Category	Transition metal
Period	4
Group	10
Block	d-block
Noble gas notation	[Ar] 3d8 4s2
Full electron configuration	1s2 2s2 2p6 3s2 3p6 3d8 4s2
Electrons per shell	2, 8, 16, 2

Atomic mass: IUPAC CIAAW abridged standard atomic weights, 2024. Most abundant isotope: NIST Atomic Weights and Isotopic Compositions.

Measured properties of nickel

From PubChem, the US National Institutes of Health. Public domain.

Melting point	1728 K (1454.9 °C), 32nd of 103 by melting point
Boiling point	3186 K (2912.9 °C), 36th of 93 by boiling point
Density	8.912 g/cm³, 33rd of 96 by density
State at room temperature	Solid
Electronegativity	1.91 (Pauling), 35th of 95 by electronegativity
Van der Waals radius	163 pm, 89th of 99 by atomic radius
First ionisation energy	7.64 eV (737 kJ/mol), 41st of 102 by first ionisation energy
Electron affinity	1.156 eV (111.5 kJ/mol), 19th of 57 by electron affinity
Common oxidation states	+3, +2
Discovered	1751

Each rank counts down from the highest value, among the elements PubChem’s table gives one for, and links to that property ranked across the whole table. All of them are collected under periodic trends.

Nickel electron configuration

The full electron configuration of nickel is 1s2 2s2 2p6 3s2 3p6 3d8 4s2. With the noble-gas core collapsed it is [Ar] 3d8 4s2, and the outermost subshell is 4s2.

Bohr model of nickel (Ni): a nucleus and four shells holding 2, 8, 16 and 2 electrons from the inside out. — Bohr model of nickel (Ni). Image © ScienceQuest, CC BY 4.0: free to reuse with credit to ScienceQuest and a link to this page, as the image licence explains.

Orbital box diagram of nickel (Ni), 1s2 2s2 2p6 3s2 3p6 3d8 4s2: one box per orbital, filled by Hund’s rule, showing two unpaired electrons, in 3d. — Orbital diagram of nickel (Ni). Image © ScienceQuest, CC BY 4.0: free to reuse with credit to ScienceQuest and a link to this page, as the image licence explains.

Why group and block follow from this is set out in how the periodic table maps electron configuration, and the electron configuration of every element is listed on one page.

Mass of one nickel atom

A molar mass is grams per mole, so dividing by the Avogadro constant gives the mass of a single atom, or for an element with more than one natural isotope the average mass of its atoms, and the reciprocal gives how many atoms sit in a gram.

Mass of one atom

one atom = 58.693 / (6.02214076 × 10²³)
= 9.7462 × 10⁻²³ g

Atoms in one gram

atoms per gram = 6.02214076 × 10²³ / 58.693
= 1.0260 × 10²² atoms

Nickel on the periodic table

Nickel is in period 4, group 10, in the d-block.

The other elements of group 10 are palladium, platinum and darmstadtium.