Published in The Delineator, Sept. 1909. Reprinted as the introduction to Rewards and Fairies in 1910. In physics, a metal is generally regarded as any substance capable of conducting electricity at a temperature of absolute zero. [2] Many elements and compounds that are not normally classified as metals become metallic under high pressures. For example, the nonmetal iodine gradually becomes a metal at a pressure of between 40 and 170 thousand times atmospheric pressure. Equally, some materials regarded as metals can become nonmetals. Sodium, for example, becomes a nonmetal at pressure of just under two million times atmospheric pressure. In astrophysics the term "metal" is cast more widely to refer to all chemical elements in a star that are heavier than helium, and not just traditional metals. In this sense the first four "metals" collecting in stellar cores through nucleosynthesis are carbon, nitrogen, oxygen, and neon, all of which are strictly non-metals in chemistry. A star fuses lighter atoms, mostly hydrogen and helium, into heavier atoms over its lifetime. Used in that sense, the metallicity of an astronomical object is the proportion of its matter made up of the heavier chemical elements. [3] [4]

Another life-enabling role for iron is as a key constituent of hemoglobin, which enables the transportation of oxygen from the lungs to the rest of the body. The gas collected in the boiling tube can be tested for hydrogen - a lighted wooden splint makes a popping sound in a boiling tube of hydrogen. Displacement reaction for a metal - a more reactive metal will displace a less reactive metal from its compounds Most metals are solid at room temperature, but this does not have to be the case. Mercury is liquid. Alloys are mixtures, where at least one part of the mixture is a metal. Examples of metals are aluminium, copper, iron, tin, gold, lead, silver, titanium, uranium, and zinc. Well-known alloys include bronze and steel.Alloys specially designed for highly demanding applications, such as jet engines, may contain more than ten elements. Metals are relatively good conductors of heat. The electrons in a metal's electron cloud are highly mobile and easily able to pass on heat-induced vibrational energy. Hadhazy A. 2016, " Galactic 'Gold Mine' Explains the Origin of Nature's Heaviest Elements", Science Spotlights, 10 May 2016, accessed 11 July 2016.

Potassium and sodium are much too dangerous to react with dilute acid! The reaction is dangerously fast and potentially explosive. Summary Metal

From about 500 BCE sword-makers of Toledo, Spain, were making early forms of alloy steel by adding a mineral called wolframite, which contained tungsten and manganese, to iron ore (and carbon). The resulting Toledo steel came to the attention of Rome when used by Hannibal in the Punic Wars. It soon became the basis for the weaponry of Roman legions; such swords were, "stronger in composition than any existing sword and, because… [they] would not break, provided a psychological advantage to the Roman soldier." [39] Antiquity The Artemision Bronze [n 8] showing either Poseidon or Zeus, c.460BCE, National Archaeological Museum, Athens. The figure is more than 2m in height. Here is a list of metals, their location on the periodic table, their properties, and uses. Properties of Metals A longtime goal of the alchemists was the transmutation of base metals into precious metals including such coinage metals as silver and gold. Most coins today are made of base metals with low intrinsic value; in the past, coins frequently derived their value primarily from their precious metal content. In astronomy, a metal is any element other than hydrogen or helium. This is because these two elements (and sometimes lithium) are the only ones that form outside stars. In the sky, a spectrometer can see the signs of metals and show the astronomer the metals in a star.