The properties of zinc vary depending on context. Physically, zinc has similar properties to other related metals on the periodic table, such as iron. Brass is a malleable alloy made from zinc and copper. Chemically, zinc shares properties with other group 12 elements and is moderately reactive. Biologically, the properties of zinc play an important role in metabolism, because many enzymes use zinc.
Zinc appears as a metal with a silver or bluish-white color. It can be shiny, but many grades have a dull finish. At everyday temperatures, one of the properties of zinc is brittleness. This means that when zinc is stretched or compressed, it tends to break rather than deform. Though the atomic weight of zinc is heavier than iron, it is less dense and, therefore, feels lighter.
A common alloy made from zinc is brass. Brass is made by mixing zinc and copper, typically with more copper than zinc. It appears as a shiny metal with a gold or yellow color. It is used for applications that require low-friction contact between surfaces. Brass tends to kill germs, so brass doorknobs are often used in hospitals to improve sanitation. It is also used extensively to make musical instruments.
The chemical properties of zinc are similar to other group 12 elements such as cadmium and mercury. Like these other elements, zinc has relatively low melting and boiling points. Zinc is somewhat reactive, meaning that it will chemically react with air and water. When pure zinc is exposed to the atmosphere, it will react with carbon dioxide to form a protective layer of zinc carbonate. The chemical properties in zinc are used in fireworks to create smoke effects.
The biological properties of zinc, on the other hand, are important for public health. In fact, zinc is found in a wide variety of organisms. The element is used in many enzymes, which are proteins that influence the rates of certain chemical reactions. Enzymes are important for maintaining chemical balance in an organism. In the human body, zinc plays a critical role in the brain and is necessary for the learning process.
Zinc deficiency is a common nutritional problem in developing countries. In childhood and adolescence, a lack of zinc can stunt growth and sexual maturity. At all ages, improper zinc levels can hinder the immune system’s ability to fight off infection and disease. It is believed that at least a quarter of the world population is at risk of zinc deficiency.