In some respects zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state (+2), and the Zn2+ and Mg2+ ions are of similar size. Corrosion-resistant zinc plating of iron (hot-dip galvanizing) is the major application for zinc. Coating of steel constitutes the largest single use of zinc, but it is used in large tonnages in zinc alloy castings, as zinc dust and oxide, and in wrought zinc products. About 70% of the world’s zinc originates from mining, while the remaining 30% comes from recycling secondary zinc.
Protons and Neutrons in Zinc
Zinc is a chemical element with atomic number 30 which means there are 30 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 Zinc are 64; 66-68; 70.
Main Isotopes of Zinc
Five stable isotopes of zinc occur in nature, with 64Zn being the most abundant isotope (49.17% natural abundance).
Zinc-64 is composed of 30 protons, 34 neutrons, and 30 electrons.
Zinc-66 is composed of 30 protons, 36 neutrons, and 30 electrons.
Zinc-67 is composed of 30 protons, 37 neutrons, and 30 electrons.
Zinc-68 is composed of 30 protons, 38 neutrons, and 30 electrons.
Zinc-70 is composed of 30 protons, 40 neutrons, and 30 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 Zinc is 30. 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 Zinc is [Ar] 3d10 4s2.
Possible oxidation states are +2.
Zinc has an electron configuration of [Ar]3d104s2 and is a member of the group 12 of the periodic table. It is a moderately reactive metal and strong reducing agent. The surface of the pure metal tarnishes quickly, eventually forming a protective passivating layer of the basic zinc carbonate, Zn5(OH)6(CO3)2, by reaction with atmospheric carbon dioxide.
The chemistry of zinc is dominated by the +2 oxidation state. When compounds in this oxidation state are formed, the outer shell s electrons are lost, yielding a bare zinc ion with the electronic configuration [Ar]3d10.
Most Important Alloy of Zinc
Zamak is a family of alloys with a base metal of zinc and alloying elements of aluminium, magnesium, and copper. Alloys of zinc with small amounts of copper, aluminium, and magnesium are useful in die casting as well as spin casting, especially in the automotive, electrical, and hardware industries. Zinc alloys have low melting points, require relatively low heat input, do not require fluxing or protective atmospheres. Because of their high fluidity, zinc alloys can be cast in much thinner walls than other die castings alloys, and they can be die cast to tighter dimensional tolerances.
|Number of protons||30|
|Number of neutrons (typical isotopes)||64; 66-68; 70|
|Number of electrons||30|
|Electron configuration||[Ar] 3d10 4s2|
Properties of other elements