Zinc is a metallic element which has been used by humans for millennia. Zinc's chemical symbol is Zn and its atomic number is 30. It belongs to the fourth period and twelfth group of the periodic table of elements. In its natural form, zinc is a blue-gray metal. It is found in abundance throughout the environment and is an essential element for people and animals.
Zinc has an atomic weight of 65.409 and a density of 7.13 grams per cubic centimeter. It is naturally existent in soil, water, and the atmosphere, per the Department of Health and Human Services. Zinc, along with cadmium and mercury, comprise group twelve of the periodic table. Zinc is a member of the transition metals family of the periodic table; its melting point of 419.6 degrees Celsius is the lowest among all transition metals. Its boiling point is 907.0 degrees Celsius.
According to the Jefferson Lab of the Department of Energy, zinc has five isotopes, four of which are stable: zinc-64, zinc-66, zinc-67, and zinc-68. These represent over 99 percent of its natural abundance with zinc-64 being the most common. There are 22 radioactive isotopes of zinc.
According to the U.S. Geological Survey, zinc is the 23rd most common element on the planet and it is the fourth most commonly produced metal in the world. It is frequently used in the process of galvanization, which gives a protective coating to metals more vulnerable to corrosion. With copper, zinc is a main element in brass. It is also found in certain types of bronze and some coins. Zinc is frequently a component in various paints, rubber, x-ray sheets, and cosmetics.
Zinc plays an important role in the human body. The Linus Pauling Institute at Oregon State University reports that zinc is an important element in the body's immune system, cell division and growth, and neurologically. When the body is deficient in zinc, growth is slowed, wounds can take an unusually long time to heal, and the senses of taste and sight can be impaired. The average woman should receive about eight milligrams and the average man eleven milligrams of zinc per day. Dietary zinc is usually found in foods that are rich in protein including most meats and nuts.
The chemical properties of zinc make it useful for galvanization, protecting metals which are more susceptible to corrosion. It is also an important dietary mineral in the human body; dietary zinc is found in foods like beef, pork, and nuts. In the environment, it is found throughout the Earth's crust, in air, water, and the soil.