Nickel is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile. The global production of nickel is presently used as follows: 68% in stainless steel; 10% in nonferrous alloys; 9% in electroplating; 7% in alloy steel; 3% in foundries; and 4% other uses (including batteries).
Nickel is extracted by roasting to NiO and then reducing with carbon. The Mond process is used to manufacture pure nickel, in which impure nickel reacts with carbon monoxide (CO) to form Ni(CO)4, which is then decomposed at 200 °C to yield 99.99% Ni.
Protons and Neutrons in Nickel
Nickel is a chemical element with atomic number 28 which means there are 28 protons in its nucleus. Total number of protons in the nucleus is called the atomic number of the atom and is given the symbol Z. The total electrical charge of the nucleus is therefore +Ze, where e (elementary charge) equals to 1,602 x 10-19 coulombs.
The total number of neutrons in the nucleus of an atom is called the neutron number of the atom and is given the symbol N. Neutron number plus atomic number equals atomic mass number: N+Z=A. The difference between the neutron number and the atomic number is known as the neutron excess: D = N – Z = A – 2Z.
For stable elements, there is usually a variety of stable isotopes. Isotopes are nuclides that have the same atomic number and are therefore the same element, but differ in the number of neutrons. Mass numbers of typical isotopes of Nickel are 60; 61; 62; 64.
Main Isotopes of Nickel
Naturally occurring nickel is composed of five stable isotopes; 58Ni, 60Ni, 61Ni, 62Ni and 64Ni, with 58Ni being the most abundant (68.077% natural abundance).
Nickel-58 is composed of 28 protons, 30 neutrons, and 28 electrons. Nickel-58 is the most abundant isotope of nickel, making up 68.077% of the natural abundance.
Nickel-60 is composed of 28 protons, 32 neutrons, and 28 electrons.
Nickel-61 is composed of 28 protons, 33 neutrons, and 28 electrons. Nickel-61 is the only stable isotope of nickel with a nuclear spin (I = 3/2), which makes it useful for studies by EPR spectroscopy.
Nickel-62 is composed of 28 protons, 34 neutrons, and 28 electrons. Nickel-62 has the highest mean nuclear binding energy per nucleon of any nuclide, at 8.7946 MeV/nucleon. Its binding energy is greater than both 56Fe and 58Fe, more abundant elements often incorrectly cited as having the most tightly bound nuclides.
Nickel-64 is composed of 28 protons, 36 neutrons, and 28 electrons.
Electrons and Electron Configuration
The number of electrons in an electrically-neutral atom is the same as the number of protons in the nucleus. Therefore, the number of electrons in neutral atom of Nickel is 28. Each electron is influenced by the electric fields produced by the positive nuclear charge and the other (Z – 1) negative electrons in the atom.
Since the number of electrons and their arrangement are responsible for the chemical behavior of atoms, the atomic number identifies the various chemical elements. The configuration of these electrons follows from the principles of quantum mechanics. The number of electrons in each element’s electron shells, particularly the outermost valence shell, is the primary factor in determining its chemical bonding behavior. In the periodic table, the elements are listed in order of increasing atomic number Z.
Electron configuration of Nickel is [Ar] 3d8 4s2.
Possible oxidation states are +2,3.
The most common oxidation state of nickel is +2, but compounds of Ni0, Ni+, and Ni3+ are well known, and the exotic oxidation states Ni2−, Ni1−, and Ni4+ have been produced and studied. Pure nickel, powdered to maximize the reactive surface area, shows a significant chemical activity, but larger pieces are slow to react with air under standard conditions because an oxide layer forms on the surface and prevents further corrosion (passivation).
Most Important Alloy of Nickel
Nickel-based superalloys currently constitute over 50% of the weight of advanced aircraft engines. Nickel-base superalloys include solid-solution-strengthened alloys and age-hardenable alloys. Age-hardenable alloys consist of an austenitic (fcc) matrix dispersed with coherent precipitation of an Ni3(Al,Ti) intermetallic with an fcc structure. Ni-based superalloys are alloys with nickel as the primary alloying element are preferred as blade material in the previously discussed applications, rather than Co- or Fe-based superalloys. What is significant for Ni-based superalloys is their high strength, creep and corrosion resistance at high temperatures. It is common to cast turbine blades in directionally solidified form or single-crystal form. Single-crystal blades are mainly used in the first row in the turbine stage.
|Number of protons||28|
|Number of neutrons (typical isotopes)||60; 61; 62; 64|
|Number of electrons||28|
|Electron configuration||[Ar] 3d8 4s2|
Properties of other elements