Aluminum is a chemical element, widely recognized for its characteristic silvery-white appearance. It is one of the most common metals used in modern society, valued for its lightweight nature and impressive ability to withstand environmental wear. This combination of properties makes aluminum a frequently chosen material for everything from beverage containers to aerospace components.
What Makes Aluminum an Element
A chemical element is a pure substance composed entirely of atoms that share the same number of protons in their nucleus. This number is the atomic number and is the unique identifier for every element on the periodic table. Aluminum’s atoms have exactly 13 protons, designating its atomic number as 13.
The element is represented by the chemical symbol Al, and its location on the periodic table is in Group 13. Aluminum is defined as a metal and cannot be broken down into simpler chemical substances. Its atoms are the smallest unit that retains the specific chemical identity of aluminum.
An aluminum atom has 13 electrons orbiting the nucleus, which determine its chemical behavior. With three electrons in its outermost shell, aluminum readily participates in chemical reactions by forming a positive ion with a charge of +3. This tendency to lose electrons explains its high reactivity, which plays a significant role in how the element is found in nature.
Physical Properties and Natural Abundance
Aluminum is notably a low-density metal, weighing only about one-third as much as steel, which is why it is used extensively in the transportation sector. In its pure form, the metal is soft, malleable, and ductile, allowing it to be easily rolled into thin foil or drawn into wire.
The element is an excellent conductor of both heat and electricity, second only to copper among common metals for electrical conductivity. While aluminum is chemically reactive, it exhibits strong corrosion resistance due to a process called passivation. When exposed to air, the metal instantly forms a microscopically thin, tough layer of aluminum oxide on its surface, which acts as a protective barrier against further oxidation and environmental degradation.
Aluminum is the most abundant metallic element, constituting approximately 8.2% of the Earth’s crust by weight. It is the third most abundant element overall in the crust, exceeded only by oxygen and silicon. The element is never found in its pure metallic state in nature because of its strong affinity for oxygen. Aluminum naturally occurs in compounds, with its primary commercial source being the sedimentary rock known as bauxite ore.