What is sodium? |

Sodium is one of about one hundred chemical elements, the mineral substances that make up everything in the universe. Sodium is one of the most vital chemical characteristics of animal life, which could not exist without it. Because of sodium's high reactivity—its ability to combine with other elements to form compounds—people have used sodium for a variety of purposes, including to make rock salt, baking soda, and table salt. Though nearly all foods in human diets contain some amount of sodium, consuming too much of it over long periods can cause a range of health problems such as hypertension and kidney disease.

The Chemistry of Sodium

Pure sodium is a semisolid silver metal with a softness and composition like butter. Because it lacks much density—solidity or compactness—sodium is extremely light and can float on water. As with many metals, it conducts, or transmits, electricity and heat extremely well.

The
periodic table of the elements
, a scientific chart containing chemical information for all known elements, reveals more specific facts about sodium. Its chemical symbol, the lettered representation of an element's name, is "Na," which is derived from the ancient Latin word for sodium, natrium. The name "sodium" itself descends from the Latin sodanum, a word that past civilizations gave to a form of sodium that alleviated headaches. English-speaking people later referred to this chemical as “soda.”

The periodic table also provides information about sodium's atomic state. An atom is the most basic chemical unit of everything that exists. One atom of sodium has an atomic number of 11. An element's atomic number is determined by the number of protons and electrons, two types of subatomic particles, contained within one of its atoms. An atom of sodium therefore has eleven of each of these particles.

One of sodium's defining traits is its reactivity. The element is so versatile and so easily combines with other elements that it cannot be found in pure form in nature. Rather, sodium must be chemically extracted from compound substances such as sodium chloride, the rock salt that forms naturally in oceans. Over many years, people around the world have discovered myriad uses for sodium and the range of compounds it can help create.

Human Uses of Sodium

Sodium compounds have been used to create now-commonplace household products such as baking soda (sodium bicarbonate), soda (sodium carbonate), paper and photographs (sodium sulfate), and borax (sodium borate), the chemical used in laundry detergents. Sodium also can be combined with small amounts of the element neon to create sodium vapor lamps. These lights are bright and inexpensive to maintain, which is why they commonly are used in stadiums and on highways.

The most common natural compound of sodium is sodium chloride, composed of sodium and chlorine, the same substance that forms oceanic rock salt. People have used this naturally occurring chemical to manufacture road salt, which is used in winter to melt snow and ice on roads. Sodium chloride also can be mixed with water and applied to pottery and ceramics as a salt glaze finish. A related process involves making substances called frits. Essential components in glassmaking, frits are made from sodium carbonate created from a sodium chloride base.

A highly popular domestic use of sodium chloride is table salt. Salt is used for many culinary purposes, including cooking, baking, preserving perishable foods, and adding extra flavor to prepared meals. Edible salt was an especially valuable commodity in less industrialized times, when countries around the world sometimes raided foreign salt mines to build up their own supplies. Although the human body requires a certain daily amount of sodium, too much can instigate a range of health problems, including increased risk of heart attack and stroke.

Sodium and Health

In proper amounts, sodium is essential to human health. It helps regulate blood pressure and blood volume while also allowing muscles to expand and contract as they should. Healthy foods that contain natural quantities of sodium include milk, celery, beets, and a variety of other vegetables and fruits. Most of the processed foods available in grocery stores and restaurants, however, contain added sodium, which has been cooked or baked into the items and is impossible to separate. Foods generally high in added sodium include snack foods such as potato chips, canned foods, and frozen meats such as sausage and bacon.

Eating any of these foods in excess can raise a person's daily sodium intake to well above the healthy recommended amount. The United States Centers for Disease Control and Prevention (CDC) suggests that healthy adults younger than fifty-one consume no more than 2,300 milligrams of sodium daily. The CDC also urges adults older than fifty-one, especially those with histories of diabetes or heart, liver, or kidney disease, to limit their daily sodium intake to 1,500 milligrams because consuming too much sodium over an extended period can lead to
hypertension
, or high blood pressure. Hypertension strains the body's blood vessels; over time, this strain can increase a person's risk of suffering a heart attack or stroke.

To counteract the negative effects of excess sodium in the body while also contributing to overall good health, people should consume about 4,700 milligrams of potassium a day, according to the CDC. Potassium directly opposes sodium, working to lower blood pressure and ultimately benefit heart health. Foods naturally high in potassium include bananas, potatoes, fresh beans, broccoli, and carrots.

Bibliography

Hamer, Frank, and Hamer, Janet. "Alphabetical Entries." The Potter's Dictionary of Materials and Techniques. 5th ed. London: A&C Black Publishers Ltd., 2004, 342–344. Print.

Krebs, Robert E. "Guide to the Elements." The History and Use of Our Earth's Chemical Elements. 2nd ed. Westport, CT: Greenwood Press, 2006, 50–52. Print.

"Salt." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention. Web. 23 Dec. 2014. http://www.cdc.gov/salt/

"Sodium in Diet." Medline Plus. U.S. National Library of Medicine. Web. 23 Dec. 2014. http://www.nlm.nih.gov/medlineplus/ency/article/002415.htm