Metals Definition and 340 Threads

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. Metals are typically malleable (they can be hammered into thin sheets) or ductile (can be drawn into wires). A metal may be a chemical element such as iron; an alloy such as stainless steel; or a molecular compound such as polymeric sulfur nitride.
In physics, a metal is generally regarded as any substance capable of conducting electricity at a temperature of absolute zero. 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 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). Around 95 of the 118 elements in the periodic table are metals (or are likely to be such). 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.
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.Metals, as chemical elements, comprise 25% of the Earth's crust and are present in many aspects of modern life. The strength and resilience of some metals has led to their frequent use in, for example, high-rise building and bridge construction, as well as most vehicles, many home appliances, tools, pipes, and railroad tracks. Precious metals were historically used as coinage, but in the modern era, coinage metals have extended to at least 23 of the chemical elements.The history of refined metals is thought to begin with the use of copper about 11,000 years ago. Gold, silver, iron (as meteoric iron), lead, and brass were likewise in use before the first known appearance of bronze in the 5th millennium BCE. Subsequent developments include the production of early forms of steel; the discovery of sodium—the first light metal—in 1809; the rise of modern alloy steels; and, since the end of World War II, the development of more sophisticated alloys.

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  1. H

    A Hall coefficient's finite temperature experiments in metals

    There are lots of measurements showing strong temperature ($T$) dependence of Hall coefficient ($R_H$) in correlated materials (eg. cuprate superconductors and other oxide materials) and such plots are available in many recent experimental papers. However, I could not find any $R_H$ vs $T$ plot...
  2. L

    Thermal Conductivites between two dissimilar metals

    1. Homework Statement I've been failing to find examples dealing with "longitudinal" thermal conductivity and how two objects in contact with each other would affect the heat flow compared to not being in contact at all. Problem: Given the following information, determine the thermal energy...
  3. Kaiera Ai Tanay

    I Modulus in Metals versus Sound Vibration

    So I'm trying to understand how the modulus works in metals. I understand that when the temperature rises, that means that the modulus decreases. But I do not understand exactly what it is or how it affects the way that the molecules would vibrate for instance, as kinetic sound energy moved...
  4. R

    A Conductive metals that are not prone to sputtering

    Does anyone know if there are highly conductive metals (or any conductive metals) that are not prone to sputtering. Or any non metalic conductors that don't sputter?
  5. A

    Finding Specific Heat of Unknown Metal

    Homework Statement I'm asked to find the specific heat of Metal X in this simulation: http://group.chem.iastate.edu/Greenbowe/sections/projectfolder/flashfiles/thermochem/heat_metal.html Mass of Metal X = 120 g Temp of Metal X = 220 degrees Mass of Water = 30 g Initial Temp of Water = 20...
  6. B

    B Why are there only two colorful metals?

    I think there are only two metals, Copper and Gold , that exhibits some color other than silver or gray. I went to a science exhibition where samples of almost all metals where kept, I think I could only see Copper and Gold having different colors. Why is it so ? why not other metals show colors ?
  7. bluejay27

    I Heavy metals and semiconductors

    Is there a list of semiconductors that are heavy metals?
  8. Gary Weller

    Is there permanent size loss in metals from contraction?

    I install automatic pool covers for a living. The tracks that our cover rides on are composed of extruded anodized aluminum. These tracks come in 22' lengths. Usually there is more than one section of track, set end to end, on a given side of the pool. We drill and anchor these sections to...
  9. M

    How Do Free Electrons Influence Metal's Conductivity and Shininess?

    I would like to ask how free electrons make metals conduct heat and electricity? Metals seem dull, their surfaces are shiny and reflect the light? So are these properties also related to free electrons? I don't know true word for dull but it might mean the light cannot go through a dull object...
  10. J

    B Fermi Level in Metals: Exploring Effects on Conductivity

    Hi, I have started looking at the fermi level and how it relates to the behaviour of conductors. It is my understanding from what I have read that the fermi level is the top of the fermi sea of filled energy states when the material is at T = 0K. 1) Is the fermi level inside the conduction...
  11. Sudhir Regmi

    A Spin magnetic moment in half metals.

    I read that the stoichiometric half-metallic compound has integer spin moment. For this, n(up)-n(down) should be integer. Since n(up) +n(down) is always integer, either n(up) or n(down) should be integer to make total spin moment integer. I could not understand how the presence of energy gap in...
  12. D

    Voltage vs Resistance. (Temperature analogy for metals)

    Hello everyone, From what i know electrical resistance for metals is a constant, but in fact it varies with temperature but not voltage. Explanation for metals and temperature is something like "heat, which is in fact average speed of electrons, does obstruct tranmission of other electrons...
  13. hernando Jose

    Is there a table of Viscosity vs Temp for metals (liquid state)?

    [moderator's note: I've decided to allow this question despite the lack of the formatting template - gneill] ladies and gentlemen, my most cordial greeting to you. i write here cause i need a viscosity vs Temperature data table about liquid metals (more specific pure Post-transition metal...
  14. F

    Lemon battery without copper and zinc metals

    Hello, I have seen a video online that shows how a LED can be lit using a single lemon without using a copper and a zinc nail. They simply stick the LED into the lemon. What does that work? I know the lemon contains the electrolyte but don't we always need to dissimilar metals for the battery...
  15. S

    Metals touching, produce EM waves

    Can you help me on this question I had for years? Every time I touch two metals together (holding them with my fingers) and place a shortwave SSB radio nearby, I hear clicks and noises on the radio. Why is that happenning? Has anyone observed this phenomenon before?
  16. Carlos de Meo

    Complex dielectric constant -- metals, insulators and Reflections

    Hi everyone Can anyone help me understanding the physical meaning for the complex dielectric constant? Assuming a electromagnetic wave from air to a conductor, the following equation is valid R= ((n-1)2+k2)/((n+1)2+k2) where K is the extinction coefficient (the complex part of the complex...
  17. T

    Which Metals Can Nickel Reduce?

    Homework Statement Homework EquationsThe Attempt at a Solution If a metal was to plate out, it means nickel is a stronger reductant therefore more negative standard reduction potential. 3 metals have a higher standard reduction potential so they will are weaker reductants than nickel. So is...
  18. Twigg

    I Interpreting the Permittivity of Metals

    In a dielectric material, permittivity makes sense, because it's easy enough to interpret the polarization density as the number density of molecules times their induced dipole moment. I'm basing this description off chapter 4 of Griffith's E&M textbook. In this model, the charges are all...
  19. H

    A Relation between IR radiation and warming in metals

    As far as I know, in most of metals, IR radiation is reflected almost entirely and is not absorbed by metals. How does a metal become warmed under IR radiation? or does reflection, on its own, can warm up a metal?
  20. nmbr28albert

    I Reflectance of metals at low frequencies

    When calculating the dielectric constant of metals using the Drude model, in the low frequency regime (infrared and beyond) one gets an approximately pure imaginary value: $$\epsilon(\omega) \approx i\frac{4\pi n e^2\tau}{m_e\omega}$$ which gives an absorption coefficient: $$\alpha(\omega)...
  21. B

    Which metals undergo differential aeration corrosion?

    Hi, I am trying to learn about different types of corrosion. I have read that iron can undergo differential aeration corrosion, but not zinc and aluminium. I do not see why...both can be reduced by oxygen and both have a passive film. Can somebody explain why? Thanks
  22. S

    I What factors influence the crystal structure of metals?

    What determines the crystal structure taken by metals? For example Sr has FCC and Ba BCC. The packing fraction is greater for FCC. However, due apparently to coordination number and number of "next nearest" neighbors, BCC is favored in the case of Barium despite its lower packing fraction...
  23. R

    Ceramics cannot be strengthened the same way as metals....

    Can someone please confirm, that there is no such thing as solution hardening or particulate hardening in ceramics? I believe you cannot do the processes mentioned. I'm not entirely sure why though. I just say because the ceramic will fracture.
  24. Dimani4

    A Fermi energy Ef changes with applied electric field?

    Hi people, I don't understand why when we apply the electric field to the metal Ef remains the same. Ef as translation energy of electrons remains the same but we accelerate the electrons with applied electric field so the translation energy increases too? In other hand according the formula...
  25. R

    I Velocity saturation and mobility in metals and semiconductor

    Hi, Lately, I've been trying to compare and understand conduction properties of metals and semiconductors. However, there are two question on my mind that I'm still trying to figure out. Maybe someone here might be able to provide some clues. 1. It is known that a linear increase of the...
  26. T

    Why is diamond stronger than metals?

    I know the reasons that diamonds are stronger than covalent materials and ionic compounds. The former is weaker because there are intermolecular forces and the latter is weaker because if pressure is applied like charged ions would be forced together making it brittle. However, I cannot think...
  27. A

    Need advice on ways to heat up metals

    Hey everyone, I am posting because I need some help. I have a project idea that I really want to pursue but I am not well educated when it comes to physics and chemical related topics. I want to know what are the different ways to heat up metals, but also which metals would that procedure work...
  28. T

    Why do transition metals have multiple oxidation states?

    I have googled it and cannot find anything. Apparently the rule that transition metals want full or half-full orbitals is false. I understand why the 4s orbital would be lost but I don't understand why some d electrons would be lost. For example in Mn6+, the electron configuration would be [Ar]...
  29. E

    Calculating number of free electrons in metals

    Hello everyone, I need your help on a question. The question is "calculate the number of free electrons per cubic centimeter (and per atom)for sodium from resistance data(relaxation time= 3.1Exp-14s)
  30. Federico Navarrete

    FDM for a 3 metal layers 3D, heat transfer

    Dear members, Some days ago, I received the following exercise but I have never studied thermodynamics before and I don't know very well where to start, the exercise is about Heat Transfer and the Finite Difference Method and I must program the solution using Petsc and C++. About the Finite...
  31. saranya_sarah

    Can Metals Evaporate? Boiling Point Explained

    If you boil metals passing their boiling point...will it evaporate? If i post this in a wrong section..im sorry and thanks in advance :)
  32. nmbr28albert

    Reflection/Absorption in Drude Metals

    One result of the Drude model of metals is that metals cannot sustain an electromagnetic wave for frequencies lower than the plasma frequency - since the wavevector is imaginary the wave will be evanescent and won't propagate. The books I've read say however, that this means the metal will...
  33. H

    Why Use Nitric Acid for Heavy Metal Digestion?

    I already done an experiment for detecting the presence of heavy metals(copper and lead) . The last step for detection is through the absorption of analyte by atomic absorption spectroscopy. Before that step to be done, the first process is to digest the water sample in the fume chamber...
  34. terryds

    Why reaction between alkali metals and water exothermic?

    Why the reaction between alkali metals and water exothermic?? I know that it produces heat to surroundings But, what actually happens?? Why it gives heat to surroundings?? http://antoine.frostburg.edu/chem/senese/101/thermo/faq/exothermic-endothermic-examples.shtml says that when forming ion...
  35. Sebastiaan

    Radiation Damage In metals from Gamma rays

    From my understanding gamma rays can damage metal, making it brittle. Fortunaly, this appears to be little, but sill if you have a lot (like in p-D fusion) it becomes a serious hazard. The question is, how much? Specificly I need to know how much damange it does in compairison to Neutron...
  36. RisingSun361

    Why Do Metals Bond in Space? Investigating the Casimir Effect

    I was drinking a bottle of tea the other day, and I noticed the cap had a claim that two metals of the same type will stick together in space. Why is this? Edit: "Why" do metals...
  37. N

    Raman Shifts of Metals for PhD Students

    hello, I'm a Phd student my Phd subject is about surface enhanced spectroscopy (SERS). i need a reference for the Raman Shifts of metals (ex: Gold (colloid or film), titan tungesten..). Plz if anyone can help me. thank you in advance Nicolas
  38. T

    Why do metals in metal carbonyls have 0 OS?

    That's pretty much it. Why do they have 0 Oxidation state?
  39. R

    Do ferrous metals become polarized when attached to mag?

    If put together a ferrous metal and a permanent magnet, does the piece of ferrous metal become oppositely polarized on its two ends, like the permanent magnet?
  40. R

    Can Acid Dissolve Metals for Conductive Coating?

    I have a rough plastic surface that I need to make very conductive. I was thinking of coating it with metal but I do not know how. Would it be possible to dissolve some copper/aluminum/nickel (or others) in acid and then pour the acid on the surface and let it dry? Would that give me a metal...
  41. K

    Does the concept of hole current hold up in metals?

    we generally talk about electron current in metals.but when an electron leaves, it leaves a hole in its place. does the hole current really exist in metals?please explain the stuff.
  42. A

    Exploring the Physics of Fermi Level in Metals

    Hi, a question please: Do all metallic substances have an equal Fermi energy level (at a constant T) ? If not, what will happen (before equilibrium) if one "fuses" together two bulks of metal with different Fermi levels (as in a PN junction) ? Since there's an abundance of energy states...
  43. F

    Metals: Physicochemical Properties for Catalytic Conversions

    hello! what are the physicochemical properties of the metals that facilitate the catalytic conversion in cars? what are their properties that make them act the way they do? ie. facilitate the reactions? I mean in electron/proton etc basics, atomic level thanks
  44. N

    Why do holes not contribute to conduction in metals?

    It seems like when an electron moves to a higher energy level, even within the same band (conduction), the empty state should be a hole. But, we are told that in metals, electrons are the charge carriers. Do I just misunderstand what holes are? Or what is going on here?
  45. R

    Why is the effective mass of electron different for metals

    ... and semiconductors? I'm trying to get some basic principles sorted in my head and I can't seem to find a straight answer to this. The lecturer drew a dispersion graph to explain it but I'm still a little confused. I understand since ##m^{*}\propto \frac{1}{\frac{\partial^2 E}{\partial...
  46. T

    List of Metals or Alloys With Fatigue Limits?

    I know that steel and titanium have fatigue limits. Just to clarify, metals or alloys with fatigue limits are metals that - as long as they experience pressures that lower than the limits - can last "indefinitely". Aluminum, for example, does NOT have a fatigue limit. No matter how small the...
  47. T

    List of metals or alloys with fatigue limit

    I know that steel and titanium have fatigue limits. Just to clarify, metals or alloys with fatigue limits are metals that - as long as they experience pressures that lower than the limits - can last "indefinitely". Aluminum, for example, does NOT have a fatigue limit. No matter how small the...
  48. Calpalned

    Metal Toxicity: Handling Cobalt and Tungsten Safely without Gloves

    Is it safe to not use a glove to handle a small block of pure cobalt metal? Is a pure tungsten rod safe too? Are there any long term effects? Thank you so much.
  49. A

    Fermi energy in metals approximately doubling

    Between Cs and Na, the fermi energy in metal approximately doubles. why doesn't the carrier concentration also double?
  50. Robsta

    Lead's melting point as a function of pressure (Thermo')

    Homework Statement When lead is melted at atmospheric pressure, the melting point is 600K, the density decreases from 1.101x104 to 1.065x104 kgm-3. The latent heat is 24.5 kJ kg-1 Estimate the melting point of lead at a pressure of 100 atm. Homework Equations I haven't been able to find any...
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