Scientific Reference
- Use group headers (Alkali, Alkaline Earth, Transition, etc.)
- Under each group, a Markdown table with key fields:
- ID, Symbol, Name, Atomic No., Category, Block, State
- Etymology
- Morpheme Breakdown (Logos Etymon)
- Semantic Role
- Interdisciplinary Fields
- Material Class
- Functional Property
- Nuclear Reference
- Discovery
Periodic Table
Alkali Metals
Group 1 electropositive metals; strong reducing agents; ionic bonding.
| ID | Symbol | Name | Atomic No. | Category | Block | State | Etymology | Morphemes | Semantic Role | Fields | Class | Function | Nuclear Ref | Discovery |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| elem.hydrogen | H | Hydrogen | 1 | Reactive nonmetal* | s | Gas | Greek ‘hydro’ (water) + ‘gen’ (creator) | hydro+gen | Water-former; life origin anchor | nat.chem, nat.physics, nat.bio | Nonmetal | Fuels fusion, organic base | 1H,2H stable; 3H radioactive | 1766 Cavendish |
| elem.lithium | Li | Lithium | 3 | Alkali metal | s | Solid | Greek ‘lithos’ (stone) | lithos | Stone-metal; electropositive donor | nat.chem, nat.earth, app.eng | Metal | Rechargeable batteries | 6Li,7Li stable | 1817 Arfvedson |
| elem.sodium | Na | Sodium | 11 | Alkali metal | s | Solid | From soda; Na from Latin natrium | soda/natrium | Salt-metal; electrolyte | nat.chem, nat.earth, app.eng | Metal | Glass, chemicals, nerves | 23Na stable | 1807 Davy |
| elem.potassium | K | Potassium | 19 | Alkali metal | s | Solid | Potash; K from kalium | potash+kalium | Salt-former; plant nutrient | nat.chem, nat.earth, app.med | Metal | Fertilizers, salt balance | 39K,41K stable; 40K trace | 1807 Davy |
| elem.rubidium | Rb | Rubidium | 37 | Alkali metal | s | Solid | Latin rubidus (red) | rubidus | Red-line spectral element | nat.chem, nat.physics | Metal | Research, photocells | 85Rb,87Rb stable | 1861 Bunsen/Kirchhoff |
| elem.cesium | Cs | Cesium | 55 | Alkali metal | s | Solid | Latin caesius (sky-blue) | caesius | Blue spectral lines | nat.chem, nat.physics | Metal | Atomic clocks, drilling fluids | 133Cs stable; 137Cs fission | 1860 Bunsen/Kirchhoff |
| elem.francium | Fr | Francium | 87 | Alkali metal | s | Solid | France | france | Heaviest alkali; highly unstable | nat.chem, nat.physics | Metal | Radioactive tracer | No stable isotopes | 1939 Perey |
Alkaline Earth Metals
Group 2 divalent metals; structural/biochemical roles.
| ID | Symbol | Name | Atomic No. | Category | Block | State | Etymology | Morphemes | Semantic Role | Fields | Class | Function | Nuclear Ref | Discovery |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| elem.beryllium | Be | Beryllium | 4 | Alkaline earth metal | s | Solid | From beryl (Greek beryllos) | beryllos | Light, stiff, transparent to X-rays | nat.chem, nat.earth | Metal | Aerospace, nuclear moderators | 9Be stable | 1798 Vauquelin |
| elem.magnesium | Mg | Magnesium | 12 | Alkaline earth metal | s | Solid | Magnesia, Greece | magnesia | Light, structural ion | nat.chem, nat.bio | Metal | Chlorophyll core, alloys | 24,25,26Mg stable | 1808 Davy |
| elem.calcium | Ca | Calcium | 20 | Alkaline earth metal | s | Solid | Latin calx (lime) | calx | Bone-builder, cement base | nat.chem, nat.bio | Metal | Bones, shells, concrete | 40Ca stable | 1808 Davy |
| elem.strontium | Sr | Strontium | 38 | Alkaline earth metal | s | Solid | Strontian, Scotland | strontian | Firework red coloration | nat.chem, app.eng | Metal | Pyrotechnics, ferrites | 84–88Sr stable | 1790 Crawford |
| elem.barium | Ba | Barium | 56 | Alkaline earth metal | s | Solid | Greek barys (heavy) | barys | Heavy-metal salt producer | nat.chem, app.med | Metal | Barium contrast in X-ray | 130,138Ba stable | 1808 Davy |
| elem.radium | Ra | Radium | 88 | Alkaline earth metal | s | Solid | Latin radius (ray) | radius | Radioactive luminous emitter | nat.chem, nat.physics | Metal | Legacy luminescence | No stable isotopes | 1898 Curie |
Transition Metals
d-block, variable oxidation states, catalysis, colored complexes.
| ID | Symbol | Name | Z | Cat | Block | State | Etymology | Morphemes | Semantic Role | Fields | Class | Function | Nuclear Ref | Discovery |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| elem.scandium | Sc | Scandium | 21 | Transition metal | d | Solid | From Scandia (Scandinavia) | scandia | Light transition metal | nat.chem, nat.earth | Metal | Aerospace alloys | 45Sc stable | 1879 Nilson |
| elem.titanium | Ti | Titanium | 22 | Transition metal | d | Solid | Named after Titans | titan | Strong, light | nat.chem, app.eng | Metal | Aerospace, implants | 46–50Ti stable | 1791 Gregor |
| elem.vanadium | V | Vanadium | 23 | Transition metal | d | Solid | Vanadis (Freyja) | vanadis | Colored salts, variable valence | nat.chem | Metal | Steel alloys, catalysts | 51V stable | 1830 Sefström |
| elem.chromium | Cr | Chromium | 24 | Transition metal | d | Solid | Greek chroma (color) | chroma | Color compounds, corrosion resistant | nat.chem | Metal | Stainless steel, pigments | 50–54Cr stable | 1797 Vauquelin |
| elem.manganese | Mn | Manganese | 25 | Transition metal | d | Solid | Magnesia negra | magnesia | Enzyme cofactor, steel additive | nat.chem, nat.bio | Metal | Batteries, steels | 55Mn stable | 1774 Gahn |
| elem.iron | Fe | Iron | 26 | Transition metal | d | Solid | Latin ferrum | ferrum | Mars-metal; hemoglobin core | nat.chem, nat.bio, app.eng | Metal | Steel, blood, magnets | 54–58Fe stable | Ancient |
| elem.cobalt | Co | Cobalt | 27 | Transition metal | d | Solid | German kobold (goblin) | kobold | Pigments, magnets | nat.chem, nat.bio | Metal | Alloys, vitamin B12 | 59Co stable | 1735 Brandt |
| elem.nickel | Ni | Nickel | 28 | Transition metal | d | Solid | Kupfernickel (false copper) | nickel | Stainless steel component | nat.chem, app.eng | Metal | Alloys, batteries | 58–64Ni stable | 1751 Cronstedt |
| elem.copper | Cu | Copper | 29 | Transition metal | d | Solid | Cyprus (cuprum) | cuprum | Venus-metal; conductor | nat.chem, app.eng | Metal | Wiring, coins | 63,65Cu stable | Ancient |
| elem.zinc | Zn | Zinc | 30 | Transition metal | d | Solid | German zinke (prong) | zinke | Galvanization metal | nat.chem, app.eng | Metal | Galvanized steel, alloys | 64–70Zn stable | Ancient |
| … |
Post-transition Metals
p-block metals; softer, lower melting points, form alloys, industrial uses.
| ID | Symbol | Name | Z | Category | Block | State | Etymology | Morphemes | Semantic Role | Fields | Class | Function | Nuclear Ref | Discovery |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| elem.aluminum | Al | Aluminum | 13 | Post-transition metal | p | Solid | Latin alumen (alum) | alumen | Lightweight, corrosion-resistant | nat.chem, app.eng | Metal | Aerospace, packaging | 27Al stable | 1825 Ørsted/Wöhler |
| elem.gallium | Ga | Gallium | 31 | Post-transition metal | p | Solid | Latin Gallia (France) | gallia | Melts in hand, electronics | nat.chem, app.eng | Metal | Semiconductors, LEDs | 69,71Ga stable | 1875 de Boisbaudran |
| elem.indium | In | Indium | 49 | Post-transition metal | p | Solid | Indigo spectral line | indigo | Soft, conductive | nat.chem, app.eng | Metal | Touchscreens, solders | 113,115In stable | 1863 Reich/Richter |
| elem.tin | Sn | Tin | 50 | Post-transition metal | p | Solid | Latin stannum | stannum | Jupiter-metal; alloys | nat.chem, app.eng | Metal | Bronzes, solders, plating | 112Sn,114–120Sn stable | Ancient |
| elem.thallium | Tl | Thallium | 81 | Post-transition metal | p | Solid | Greek thallos (green shoot) | thallos | Toxic green-line element | nat.chem, app.eng | Metal | Electronics, optics (limited) | 203,205Tl stable | 1861 Crookes |
| elem.lead | Pb | Lead | 82 | Post-transition metal | p | Solid | Latin plumbum | plumbum | Saturn-metal; dense, soft | nat.chem, app.eng | Metal | Batteries, shielding | 204–208Pb stable | Ancient |
| elem.bismuth | Bi | Bismuth | 83 | Post-transition metal | p | Solid | German Wismut | wismut | Dense, low-toxicity heavy metal | nat.chem, app.eng | Metal | Alloys, cosmetics, meds | 209Bi long-lived α emitter | 18th c. |
Metalloids
Semiconductors, border properties; amphoteric chemistry.
| ID | Symbol | Name | Z | Category | Block | State | Etymology | Morphemes | Semantic Role | Fields | Class | Function | Nuclear Ref | Discovery |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| elem.boron | B | Boron | 5 | Metalloid | p | Solid | Arabic buraq (borax) | buraq | Border element; neutron absorber | nat.chem, hyb.materials | Metalloid | Borosilicate glass, BN ceramics | 10,11B stable | 1808 Davy et al. |
| elem.silicon | Si | Silicon | 14 | Metalloid | p | Solid | Latin silex (flint) | silex | Earth’s crust backbone; semiconductor | nat.chem, hyb.materials | Metalloid | Electronics, photovoltaics | 28–30Si stable | 1823 Berzelius |
| elem.germanium | Ge | Germanium | 32 | Metalloid | p | Solid | Named after Germany | germania | Semiconductor, transparent to IR | nat.chem, hyb.materials | Metalloid | Optics, electronics | 70,72,73,74,76Ge stable | 1886 Winkler |
| elem.arsenic | As | Arsenic | 33 | Metalloid | p | Solid | Greek arsenikon (orpiment) | arsenikon | Toxic metalloid, poisons + semiconductors | nat.chem, nat.bio | Metalloid | GaAs semiconductors, pesticides | 75As stable | Ancient |
| elem.antimony | Sb | Antimony | 51 | Metalloid | p | Solid | Latin stibium | stibium | Semimetal; cosmetics, alloys | nat.chem, app.eng | Metalloid | Flame retardants, alloys | 121,123Sb stable | Ancient |
| elem.tellurium | Te | Tellurium | 52 | Metalloid | p | Solid | Latin tellus (earth) | tellus | Semiconductor; thermoelectrics | nat.chem, hyb.materials | Metalloid | Solar panels, alloys | 120,122,123,124,125,126Te stable | 1782 Müller |
| elem.polonium | Po | Polonium | 84 | Metalloid | p | Solid | Named after Poland | polonia | Highly radioactive border element | nat.chem, nat.physics | Metalloid | Heat source (space), alpha emitter | No stable isotopes | 1898 Curie |
Reactive Nonmetals
C, H, N, O, P, S, Se — covalent frameworks, biochemistry.
| ID | Symbol | Name | Z | Cat | Block | State | Etymology | Morphemes | Semantic Role | Fields | Class | Function | Nuclear Ref | Discovery |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| elem.carbon | C | Carbon | 6 | Reactive nonmetal | p | Solid | Latin carbo (coal) | carbo | Backbone of life; multiple allotropes | nat.chem, nat.bio | Nonmetal | Diamond, graphite, graphene | 12C,13C stable; 14C dating | Ancient |
| elem.nitrogen | N | Nitrogen | 7 | Reactive nonmetal | p | Gas | Greek nitron + gen | nitron+gen | Atmosphere base, fertilizer | nat.chem, nat.bio | Nonmetal | Ammonia, fertilizers | 14,15N stable | 1772 Rutherford |
| elem.oxygen | O | Oxygen | 8 | Reactive nonmetal | p | Gas | Greek oxys + gen | oxys+gen | Oxidizer, respiration | nat.chem, nat.bio | Nonmetal | Medical O2, combustion | 16,17,18O stable | 1774 Priestley/Scheele |
| elem.phosphorus | P | Phosphorus | 15 | Reactive nonmetal | p | Solid | Greek phosphoros (light-bearer) | phosphoros | DNA backbone, ATP | nat.chem, nat.bio | Nonmetal | Matches, fertilizers, DNA | 31P stable | 1669 Brand |
| elem.sulfur | S | Sulfur | 16 | Reactive nonmetal | p | Solid | Latin sulphur (brimstone) | sulphur | Volcano/brimstone element | nat.chem, nat.bio | Nonmetal | Vulcanization, sulfuric acid | 32,33,34,36S stable | Ancient |
| elem.selenium | Se | Selenium | 34 | Reactive nonmetal | p | Solid | Greek selene (moon) | selene | Moon-metal, semiconductor | nat.chem, nat.bio | Nonmetal | Photovoltaics, enzymes | 74,76,77,78,80,82Se stable | 1817 Berzelius |
Halogens
Group 17 electronegative nonmetals; salt formers; powerful oxidizers.
| ID | Symbol | Name | Z | Category | Block | State | Etymology | Morphemes | Semantic Role | Fields | Class | Function | Nuclear Ref | Discovery |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| elem.fluorine | F | Fluorine | 9 | Halogen | p | Gas | Latin fluere (to flow) | fluere | Salt-former; strongest oxidizer | nat.chem, nat.bio, hyb.env_sci, app.med | Nonmetal | Teflon, refrigerants | 19F stable | 1886 Moissan |
| elem.chlorine | Cl | Chlorine | 17 | Halogen | p | Gas | Greek chloros (green-yellow) | chloros | Salt-metal partner; disinfectant | nat.chem, nat.bio, hyb.env_sci, app.med | Nonmetal | PVC, bleach, disinfection | 35,37Cl stable | 1774 Scheele |
| elem.bromine | Br | Bromine | 35 | Halogen | p | Liquid | Greek bromos (stench) | bromos | Foul-smelling halogen | nat.chem, nat.bio, hyb.env_sci | Nonmetal | Flame retardants, dyes | 79,81Br stable | 1826 Balard |
| elem.iodine | I | Iodine | 53 | Halogen | p | Solid | Greek ioeides (violet-like) | ioeides | Violet halogen; thyroid hormone | nat.chem, nat.bio, app.med | Nonmetal | Antiseptics, nutrition | 127I stable | 1811 Courtois |
| elem.astatine | At | Astatine | 85 | Halogen | p | Solid | Greek astatos (unstable) | astatos | Shortest-lived halogen | nat.chem, nat.physics | Nonmetal | Radioisotope tracers | No stable isotopes | 1940 Corson/MacKenzie/Segrè |
| elem.tennessine | Ts | Tennessine | 117 | Halogen | p | Solid | Tennessee (USA) | tennessine | Superheavy halogen; predicted | nat.chem, nat.physics | Nonmetal | Research only | No stable isotopes | 2010 JINR/ORNL |
Noble Gases
Group 18 inert gases; closed shells; lighting, shielding, cryogenics.
| ID | Symbol | Name | Z | Category | Block | State | Etymology | Morphemes | Semantic Role | Fields | Class | Function | Nuclear Ref | Discovery |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| elem.helium | He | Helium | 2 | Noble gas | s | Gas | Greek helios (sun) | helios | Inert archetype; cryogenics | nat.chem, nat.physics, nat.astro, app.eng | Nonmetal | Balloons, cryogenics | 3He, 4He stable | 1868 Janssen/Lockyer |
| elem.neon | Ne | Neon | 10 | Noble gas | p | Gas | Greek neos (new) | neos | Lighting gas; inert | nat.chem, nat.physics, nat.astro, app.eng | Nonmetal | Neon lights, indicators | 20,21,22Ne stable | 1898 Ramsay/Travers |
| elem.argon | Ar | Argon | 18 | Noble gas | p | Gas | Greek argos (idle) | argos | Atmospheric noble gas | nat.chem, nat.physics, nat.astro | Nonmetal | Shielding, lighting | 36,38,40Ar stable | 1894 Ramsay/Strutt |
| elem.krypton | Kr | Krypton | 36 | Noble gas | p | Gas | Greek kryptos (hidden) | kryptos | Hidden gas; lighting | nat.chem, nat.physics | Nonmetal | Lighting, lasers | 78,80,82,83,84,86Kr stable | 1898 Ramsay/Travers |
| elem.xenon | Xe | Xenon | 54 | Noble gas | p | Gas | Greek xenos (strange) | xenos | Heavy noble gas; anesthesia | nat.chem, nat.physics, nat.med | Nonmetal | Lamps, ion propulsion, anesthesia | 124–136Xe stable | 1898 Ramsay/Travers |
| elem.radon | Rn | Radon | 86 | Noble gas | p | Gas | From radium + -on | radium | Radioactive noble gas | nat.chem, nat.physics, app.med | Nonmetal | Radiotherapy, tracer | No stable isotopes | 1900 Dorn |
| elem.oganesson | Og | Oganesson | 118 | Noble gas | p | Solid (predicted) | Named after Yuri Oganessian | oganes | Superheavy noble gas (unstable) | nat.chem, nat.physics | Nonmetal | Research only | No stable isotopes | 2002 JINR/LLNL |
Lanthanides
4f rare earths; magnetic, optical, phosphors, catalysts.
| ID | Symbol | Name | Z | Category | Block | State | Etymology | Morphemes | Semantic Role | Fields | Class | Function | Nuclear Ref | Discovery |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| elem.lanthanum | La | Lanthanum | 57 | Lanthanide | f | Solid | Greek lanthanein (to lie hidden) | lanthanein | Hidden metal; prototype of lanthanides | nat.chem, app.eng | Metal | Optical lenses, catalysts | 138–139La stable | 1839 Mosander |
| elem.cerium | Ce | Cerium | 58 | Lanthanide | f | Solid | Named after asteroid Ceres | ceres | Bright element, abundant | nat.chem, app.eng | Metal | Catalysts, lighter flints | 136,138,140,142Ce stable | 1803 Hisinger/Klaproth |
| elem.praseodymium | Pr | Praseodymium | 59 | Lanthanide | f | Solid | Greek prasios didymos (green twin) | prasio+didymos | Green-colored rare earth | nat.chem, hyb.materials | Metal | Magnets, glasses | 141Pr stable | 1885 von Welsbach |
| elem.neodymium | Nd | Neodymium | 60 | Lanthanide | f | Solid | Greek neos didymos (new twin) | neos+didymos | Magnet powerhouse | nat.chem, hyb.materials | Metal | NdFeB magnets | 142–150Nd stable | 1885 von Welsbach |
| elem.promethium | Pm | Promethium | 61 | Lanthanide | f | Solid | Named after Prometheus | prometheus | Fire-bringer; only radioactive rare earth | nat.chem, nat.physics | Metal | Nuclear batteries | No stable isotopes | 1945 (Oak Ridge) |
| elem.samarium | Sm | Samarium | 62 | Lanthanide | f | Solid | From samarskite mineral | samarskite | Strong magnets; optics | nat.chem, hyb.materials | Metal | Samarium–cobalt magnets | 144,147,148,149,150,152,154Sm stable | 1879 Lecoq |
| elem.europium | Eu | Europium | 63 | Lanthanide | f | Solid | Named after Europe | europa | Phosphor element; red emission | nat.chem, hyb.materials | Metal | Phosphors, euro notes | 151,153Eu stable | 1901 Demarçay |
| elem.gadolinium | Gd | Gadolinium | 64 | Lanthanide | f | Solid | Johan Gadolin | gadolin | MRI contrast, magnets | nat.chem, hyb.materials | Metal | MRI agents, alloys | 152,154–160Gd stable | 1880 Marignac |
| elem.terbium | Tb | Terbium | 65 | Lanthanide | f | Solid | Ytterby, Sweden | ytterby | Green phosphor element | nat.chem, hyb.materials | Metal | Phosphors, lasers | 159Tb stable | 1843 Mosander |
| elem.dysprosium | Dy | Dysprosium | 66 | Lanthanide | f | Solid | Greek dysprositos (hard to get) | dysprositos | High magnetic strength | nat.chem, hyb.materials | Metal | Magnets, reactors | 156–164Dy stable | 1886 Lecoq |
| elem.holmium | Ho | Holmium | 67 | Lanthanide | f | Solid | Holmia (Stockholm) | holmia | Magnetic resonance element | nat.chem, hyb.materials | Metal | Lasers, magnets | 165Ho stable | 1878 Per Teodor Cleve |
| elem.erbium | Er | Erbium | 68 | Lanthanide | f | Solid | Ytterby, Sweden | ytterby | Telecom optical amplifier | nat.chem, hyb.materials | Metal | Fiber optics | 162,164,166–170Er stable | 1842 Mosander |
| elem.thulium | Tm | Thulium | 69 | Lanthanide | f | Solid | Thule (mythic north) | thule | Rarest stable lanthanide | nat.chem, hyb.materials | Metal | Portable X-ray sources | 169Tm stable | 1879 Cleve |
| elem.ytterbium | Yb | Ytterbium | 70 | Lanthanide | f | Solid | Ytterby, Sweden | ytterby | Multipurpose rare earth | nat.chem, hyb.materials | Metal | Lasers, alloys | 168–176Yb stable | 1878 Marignac |
| elem.lutetium | Lu | Lutetium | 71 | Lanthanide | f | Solid | Lutetia (Paris) | lutetia | End of lanthanides | nat.chem, hyb.materials | Metal | Catalysts, PET scanning | 175Lu stable | 1907 Urbain |
Actinides
5f elements; radioactivity, nuclear fuels, and synthetic superheavies.
| ID | Symbol | Name | Z | Category | Block | State | Etymology | Morphemes | Semantic Role | Fields | Class | Function | Nuclear Ref | Discovery |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| elem.actinium | Ac | Actinium | 89 | Actinide | f | Solid | Greek aktis (ray) | aktis | First of actinides; glowing | nat.chem, nat.physics | Metal | Research, tracer | No stable isotopes | 1899 Debierne |
| elem.thorium | Th | Thorium | 90 | Actinide | f | Solid | Norse god Thor | thor | Fertile fuel (232Th) | nat.chem, nat.physics, app.eng | Metal | Thorium reactors, mantles | 232Th long-lived | 1829 Berzelius |
| elem.protactinium | Pa | Protactinium | 91 | Actinide | f | Solid | Greek protos (before) + actinium | protos+aktis | Precursor to actinium | nat.chem, nat.physics | Metal | Nuclear research | 231Pa long-lived | 1913 Hahn/Meitner |
| elem.uranium | U | Uranium | 92 | Actinide | f | Solid | Uranus (planet) | uranus | Primary fissile element | nat.chem, nat.physics, app.eng | Metal | Reactors, weapons | 235U fissile; 238U fertile | 1789 Klaproth |
| elem.neptunium | Np | Neptunium | 93 | Actinide | f | Solid | Neptune (planet) | neptune | First transuranic | nat.chem, nat.physics | Metal | Nuclear research | No stable isotopes | 1940 McMillan/Abelson |
| elem.plutonium | Pu | Plutonium | 94 | Actinide | f | Solid | Pluto (planet) | pluto | Iconic fissile, weapons fuel | nat.chem, nat.physics | Metal | Reactors, weapons | 239Pu fissile | 1940 Seaborg |
| elem.americium | Am | Americium | 95 | Actinide | f | Solid | America | america | Synthetic; detector isotope | nat.chem, nat.physics, app.eng | Metal | Smoke detectors, research | 241Am α emitter | 1944 Seaborg |
| elem.curium | Cm | Curium | 96 | Actinide | f | Solid | Marie & Pierre Curie | curie | Radioactive namesake | nat.chem, nat.physics | Metal | Research, α source | 244Cm etc. | 1944 Seaborg |
| elem.berkelium | Bk | Berkelium | 97 | Actinide | f | Solid | Berkeley, California | berkeley | Synthetic research element | nat.chem, nat.physics | Metal | Research only | No stable isotopes | 1949 Seaborg |
| elem.californium | Cf | Californium | 98 | Actinide | f | Solid | California | california | Neutron emitter | nat.chem, nat.physics | Metal | Reactor startup, neutron source | 252Cf | 1950 Seaborg |
| elem.einsteinium | Es | Einsteinium | 99 | Actinide | f | Solid | Albert Einstein | einstein | Named after physicist | nat.chem, nat.physics | Metal | Research only | No stable isotopes | 1952 (H-bomb debris) |
| elem.fermium | Fm | Fermium | 100 | Actinide | f | Solid | Enrico Fermi | fermi | Synthetic actinide | nat.chem, nat.physics | Metal | Research only | No stable isotopes | 1952 (H-bomb debris) |
| elem.mendelevium | Md | Mendelevium | 101 | Actinide | f | Solid | Dmitri Mendeleev | mendeleev | Table namesake | nat.chem, nat.physics | Metal | Research only | No stable isotopes | 1955 Seaborg |
| elem.nobelium | No | Nobelium | 102 | Actinide | f | Solid | Alfred Nobel | nobel | Synthetic; namesake of prizes | nat.chem, nat.physics | Metal | Research only | No stable isotopes | 1958 JINR |
| elem.lawrencium | Lr | Lawrencium | 103 | Actinide | f | Solid | Ernest Lawrence | lawrence | End of actinides; synthetic | nat.chem, nat.physics | Metal | Research only | No stable isotopes | 1961 Ghiorso |
118 elements across:
- Alkali metals
- Alkaline earth metals
- Transition metals
- Post-transition metals
- Metalloids
- Reactive nonmetals
- Halogens
- Noble gases
- Lanthanides
- Actinides
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Key terms in plain language
Open a term for a concise explanation of language used on this page.
VoIP
Voice over Internet Protocol carries phone calls over an IP network instead of a traditional analog phone line. Call quality depends on network stability, latency, and traffic management.
Unified Communications (UCaaS)
A cloud-based combination of business calling, messaging, meetings, presence, and collaboration tools managed as one communications service.
SIP Trunking
A service that connects a business phone system to the public telephone network using Internet Protocol, replacing or supplementing traditional phone lines.
Bandwidth
The amount of data a connection can carry in a given time, usually measured in Mbps or Gbps. More bandwidth supports more users, devices, and simultaneous applications.
Latency
The time it takes data to travel between two points. Lower latency improves voice, video meetings, cloud applications, gaming, and other real-time services.
Service-Level Agreement (SLA)
A provider’s written commitment covering service targets such as availability, response time, repair time, and sometimes financial credits when commitments are missed.