Zinc is the first element in the twelfth column of the periodic table. It is classified as a transition metal. The zinc atom has 30 electrons and 30 protons with 34 neutrons, in the most abundant isotope form.
| Symbol | Zn |
| Atomic Number | 30 |
| Atomic Weight | 65.38 |
| Classification | Transition metal |
| Phase at Room Temperature | Solid |
| Density | 7.14 grams per cm cubed |
| Melting Point | 419°C, 787°F |
| Boiling Point | 907°C, 1665°F |
| Discovered by | Known about since ancient times |
Under normal conditions, zinc is a hard, brittle, bluish-white metal. It becomes less brittle and more malleable above 100 degrees Celsius.
Zinc has relatively low melting and boiling points for metals. It is a good conductor of electricity. When zinc is exposed to air, it reacts with carbon dioxide to form a thin layer of zinc carbonate. This class protects the element from further reaction.
Zinc is quite active and soluble in most acids and some alkalis. However, it does not readily react with oxygen.
Zinc is not found in its pure elemental form, but is found in minerals in the earth’s crust, where it is the 24th most abundant element. Small traces of zinc can be found in sea water and air.
Minerals mined for zinc include sphalerite, smithsonite, hemimorphite and wurtzite. Sphalerite is the most mined because it contains a high percentage of zinc (~60%). The majority of zinc production is mined in China, Peru and Australia.
More than half of the zinc mined is used to coat other metals such as steel and iron. Galvanizing involves coating these other metals with a thin layer of zinc to prevent them from corroding or rusting.
Zinc is also used to make alloys with other metals. Brass, an alloy based on copper and zinc, has been used since ancient times. Other alloys include nickel-silver, zinc-aluminum and cadmium-zinc telluride. They are used for a variety of applications including pipe bodies, molded automotive parts, and sensing devices.
Other uses include sunscreens, ointments, concrete, paints and even propellants for model rockets.
Zinc also plays an important role in biology and is found in more than a hundred enzymes. It is used to build DNA and by brain cells used for learning.
Zinc is used with copper to create American coins. Before 1982, the coin contained 95% copper and 5% zinc. After 1982, the coin was made primarily of zinc with 97.5% zinc and 2.5% copper. Zinc is now used because it is cheaper than copper.
Zinc has been used to make brass alloys (along with copper) since ancient times. The first scientist to isolate pure metal was the German chemist Andreas Marggraf in 1746.
A German alchemist named Paracelsus named the metal zinc. It comes from the German word “zinke” meaning “pointed” (for the pointed shape of the zinc crystal) or “zinn” meaning “tin“.
There are five isotopes of zinc found in nature. The most zinc-64.
When zinc is ignited, it emits a brilliant blue flame with zinc oxide gas.
The average adult body contains 2 to 4 grams of zinc.
Foods that contain zinc include sesame seeds, wheat, beans, mustard, and nuts.
Zinc is sometimes used in toothpaste and baby powder.
Prestal metal alloy consists of 78% zinc and 22% aluminum. It’s supposed to behave like plastic, but be nearly as durable as steel.
