Roughly 80% of all known elements are metals, making them the dominant characters on the periodic table. They span an extraordinary range — from lithium, light enough to float on water, to osmium, denser than anything else on Earth; from mercury, which is liquid at room temperature, to tungsten, which will not melt until 3422°C. Despite this diversity, metals share a family resemblance: they are typically shiny, they conduct heat and electricity, and they can be hammered into sheets (malleability) or pulled into wires (ductility). All of this comes from their metallic bonding, where outer electrons roam freely through a lattice of positive ions.
Metals are the backbone of civilization. The Bronze Age, the Iron Age, the Steel Age — human history is literally named after metals. Today, copper carries our electricity, aluminum forms our aircraft, titanium replaces our hip joints, and lithium powers our phones. Iron remains king by volume: over 1.8 billion tonnes of steel are produced globally each year. Even precious metals play critical roles beyond jewelry — platinum catalyzes chemical reactions in catalytic converters, gold's resistance to corrosion makes it essential for electronics, and silver's antibacterial properties are used in medical dressings.
On the periodic table, metals occupy the left side and the center (transition metals, lanthanides, actinides). As you move left and down, metallic character increases — francium and cesium are the most metallic elements, so reactive they ignite on contact with air. Metals typically have low ionization energies, meaning they release outer electrons easily, which is why they tend to form positive ions (cations) in chemical reactions. This willingness to shed electrons is what makes metals such excellent conductors and such enthusiastic participants in chemistry.