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Cobalt (Co) – Element 27 of the periodic table

Cobalt (symbol Co) is element number 27 of the periodic table and belongs to the “Transition metal” category. Its atomic mass is about 58.933, and its phase under standard conditions is Solid. This element sits in period 4 and group 9 of the periodic table, and its electrons are arranged in shells of 2, 8, 15, 2. The short electron configuration of Cobalt is [Ar] 3d⁷ 4s². Known uses of Cobalt include Cutting tools, Lithium-ion batteries and Blue pigment.

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Properties of Cobalt

Atomic number
27
Chemical symbol
Co
Atomic mass
58.933
Category
Transition metal
Period
4
Group
9
Phase
Solid
Protons
27
Electrons
27
Neutrons (approx.)
32
Electron shells
2, 8, 15, 2
Outer-shell electrons
2
Discovered
Georg Brandt (1735)

Electron configuration of Cobalt

The electron configuration of Cobalt (Co), with 27 electrons, is shown below. The last shell (shell 4) is highlighted:

Full configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁷ 4s²
Short configuration
[Ar] 3d⁷ 4s²
Last shell
4s²

What is electron configuration and how is it written?

Electron shells of Cobalt

Distribution of 27 electrons of Cobalt across shells K to N:

  1. K2
  2. L8
  3. M15
  4. N2

What is a transition metal?

The transition metals are the d-block elements: usually good conductors of heat and electricity, with several oxidation states, and they form colourful compounds and important catalysts.

Uses of Cobalt

Frequently asked questions about Cobalt

What is the atomic number of Cobalt?

The atomic number of Cobalt (Co) is 27; that is, every atom of it has 27 protons.

What is the electron configuration of Cobalt?

The electron configuration of Cobalt (Co) is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁷ 4s²; in short form it is [Ar] 3d⁷ 4s², and its last shell is 4s².

What is the chemical symbol of Cobalt?

The chemical symbol of Cobalt is Co.

Where is Cobalt located in the periodic table?

Cobalt is located in period 4 and group 9 and belongs to the “Transition metal” category.

What is the atomic mass of Cobalt?

The atomic mass of Cobalt is about 58.933 (atomic mass units).

What is the phase of Cobalt under normal conditions?

The phase of Cobalt under standard conditions is Solid.

What are the uses of Cobalt?

Uses of Cobalt include Cutting tools, Lithium-ion batteries and Blue pigment.

Who discovered Cobalt?

Cobalt was discovered by Georg Brandt in 1735.

Elements in the same category as Cobalt (Transition metal)

Scandium (Sc)Titanium (Ti)Vanadium (V)Chromium (Cr)Manganese (Mn)Iron (Fe)Nickel (Ni)Copper (Cu)Zinc (Zn)Yttrium (Y)Zirconium (Zr)Niobium (Nb)Molybdenum (Mo)Technetium (Tc)Ruthenium (Ru)Rhodium (Rh)Palladium (Pd)Silver (Ag)Cadmium (Cd)Hafnium (Hf)

See all Transition metals

Cobalt’s group 9 neighbours

Rhodium (Rh)Iridium (Ir)Meitnerium (Mt)

Group 9 of the periodic table