Galvanized screws resist rust due to their zinc coating.
Zinc is a metallic chemical element found in reasonable abundance throughout the world. It is classified in the transition metals, along with nickel and mercury, among others. The metal is used in a variety of alloys and compounds that have a variety of uses, from sunscreen to fine art. Living organisms also rely on it as a valuable nutritional trace element; many foods are excellent sources, including seeds and whole grains.
Whole grains are a good source of dietary zinc.
Pure zinc is a shiny, bluish-white metal. It is extremely brittle at medium room temperature, although when heated it becomes soft, malleable and easily worked. When burned, it produces a bright blue to green flame, and the metal is reactive, readily combining with a variety of other elements. In the periodic table of the elements, zinc is identified with the symbol Zn and the metal has an atomic number of 30.
Zinc is used in sunscreen.
Humans have used zinc for thousands of years; the element was used extensively in India in particular. Around 1500, it began to be imported into Europe, where it was an expensive and unusual metal. Supposedly, zinc was named by Paracelsus, after the German zinke, “toothed”, to describe the way it behaved in a furnace. Around 1700, several European scientists managed to isolate the element; there is some controversy over who made it first, although many people credit Andreas Marggraf.
An excessive amount of zinc can cause stomach cramps.
In alloys such as bronze, zinc makes the metal stronger and sometimes also easier to work with. It is also used in soldering and galvanizing. Zinc oxide, a well-known compound, is a popular ingredient in sunscreens. Some batteries, pigments and coins also contain this metal. Humans need about 11 milligrams of zinc a day, most of which is absorbed from a variety of foods. Deficiency can cause hair loss, diarrhea, and sores, while excess can cause stomach cramps and anemia.
Zinc has an atomic number of 30 and the symbol for Zn in the periodic table.
Pure metallic zinc is non-toxic, but the element must be handled with care in some circumstances. Vapors can be toxic to people working with the metal while it is hot, and free ions can be very dangerous. It is important to wear proper protection when melting and heating metals in general to reduce exposure to toxic fumes. People exposed to too much zinc may have difficulty getting the minerals they need in their diet, as the metal can block absorption. Therefore, excess can lead to substantial health problems if left untreated.