The number is inexact as the boundaries between metals, nonmetals, and metalloids fluctuate slightly due to a lack of universally accepted definitions of the categories involved. Around 95 of the 118 elements in the periodic table are metals (or are likely to be such). In chemistry, two elements that would otherwise qualify (in physics) as brittle metals- arsenic and antimony-are commonly instead recognised as metalloids due to their chemistry (predominantly non-metallic for arsenic, and balanced between metallicity and nonmetallicity for antimony). Sodium, for example, becomes a nonmetal at pressure of just under two million times atmospheric pressure. Equally, some materials regarded as metals can become nonmetals. ![]() For example, the nonmetal iodine gradually becomes a metal at a pressure of between 40 and 170 thousand times atmospheric pressure. Many elements and compounds that are not normally classified as metals become metallic under high pressures. ![]() In physics, a metal is generally regarded as any substance capable of conducting electricity at a temperature of absolute zero. A metal may be a chemical element such as iron, or an alloy such as stainless steel. ![]() Metals are typically malleable (they can be hammered into thin sheets) or ductile (can be drawn into wires). A metal (from Greek μέταλλον métallon, "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well.
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