Nickel
Definition and meaning of Nickel in chemistry.
![Nickel element card: symbol Ni, atomic number 28, atomic mass 58.693, electron configuration [Ar] 3d⁸ 4s², oxidation states +2, Transition metal, group 10, period 4, solid at room temperature.](/assets/images/terms/nickel-chemical-element.webp)
Nickel is a silvery-white transition metal with the chemical symbol Ni and atomic number 28. It is a hard yet ductile metal that resists corrosion and oxidation even at high temperatures. Like iron, this element is ferromagnetic and retains its magnetic properties at room temperature.
In more detail
Nickel sits in group 10 of the periodic table as a key transition metal. In chemical reactions, nickel most commonly forms stable compounds in the +2 oxidation state. However, chemists can also prepare rarer compounds with +3 or +4 oxidation states.
In nature, nickel occurs inside metallic space meteorites and terrestrial minerals like pentlandite. Geologists believe that most of the nickel on Earth is buried deep within the metallic core. At room temperature, nickel reacts with atmospheric oxygen at an extremely slow rate.
This slow reaction allows the metal to maintain a highly reflective, shiny surface over time. Many students incorrectly assume that nickel is highly toxic in all forms and concentrations. In reality, some plants and microorganisms require tiny trace amounts of nickel to function properly.
However, direct contact with the metal can cause allergic skin reactions in sensitive individuals. Manufacturers often use electroplating to coat weaker metals with a protective layer of nickel. It also mixes easily with other metals to create robust alloys like stainless steel.
Another important nickel alloy is nichrome, which has a very high electrical resistance. Nichrome is commonly used to make heating elements in household toasters and hair dryers.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Ni |
| Atomic number | 28 |
| Atomic mass | 58.693 u |
| Category | Transition-Metal |
| Melting point | 1455 °C |
| State at STP | Solid |
Metal workers mix nickel with iron and chromium to create durable stainless steel. This popular alloy resists environmental rust and maintains its structural strength under heavy physical wear. The addition of nickel changes the crystal structure of the iron to make it more formable. Because of these beneficial traits, manufacturers use stainless steel to make kitchen utensils, medical instruments, and industrial pipes.
Frequently asked questions
Is nickel toxic to humans?
Tiny amounts of nickel are needed for some plants and microbes. However, prolonged contact with the metal can cause allergic skin rashes in sensitive individuals.
Why is nickel used in coins?
Nickel resists rust and physical wear extremely well over many decades of use. It also has a bright, shiny look that keeps coins looking clean and new.
What is electroplating and how is nickel used in it?
Electroplating uses electrical current to deposit a thin layer of nickel onto another metal object. This coating acts as a barrier that prevents the underlying metal from rusting.
Related terms
Sources & references
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