{"dataset":{"id":"b9e9e23f-82d5-4415-b9c9-a6c77d470852","slug":"periodic-table","name":"Periodic table of the elements","description":"Properties of all 118 chemical elements from the PubChem periodic table, published by NCBI at the US National Institutes of Health (a US government work). One document per element citing its PubChem element page; group and period numbers come from PubChem's element annotations.","visibility":"public","version":119,"documentCount":118,"createdAt":"2026-10-04T00:12:56.000Z","updatedAt":"2026-10-04T00:26:03.000Z","publisher":"Koskamo","license":"PubChem periodic table data (NIH/NLM, pubchem.ncbi.nlm.nih.gov/ptable); group and period from Jefferson Lab via PubChem","reviewedAt":"2026-10-04T00:26:10.000Z"},"total":118,"documents":[{"id":"9e2bcc20-65d4-45a5-9170-2584daefa449","title":"Hydrogen","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/1","version":1,"createdAt":"2026-10-04T00:13:02.000Z","updatedAt":"2026-10-04T00:13:02.000Z","text":"Hydrogen (H) is chemical element 1, a nonmetal in group 1, period 1 (PubChem).\n\n- Atomic number: 1\n- Symbol: H\n- Group: 1\n- Period: 1\n- Atomic mass: 1.0080 u\n- Electron configuration: 1s1\n- Electronegativity (Pauling scale): 2.2\n- Atomic radius (van der Waals): 120 pm\n- Ionization energy: 13.598 eV\n- Electron affinity: 0.754 eV\n- Oxidation states: +1, -1\n- Standard state: Gas\n- Melting point: 13.81 K\n- Boiling point: 20.28 K\n- Density: 0.00008988 g/cm³\n- Chemical group: Nonmetal\n- Year discovered: 1766"},{"id":"1d39b763-9553-4fc4-ab5b-530c68f95334","title":"Helium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/2","version":1,"createdAt":"2026-10-04T00:13:09.000Z","updatedAt":"2026-10-04T00:13:09.000Z","text":"Helium (He) is chemical element 2, a noble gas in group 18, period 1 (PubChem).\n\n- Atomic number: 2\n- Symbol: He\n- Group: 18\n- Period: 1\n- Atomic mass: 4.00260 u\n- Electron configuration: 1s2\n- Atomic radius (van der Waals): 140 pm\n- Ionization energy: 24.587 eV\n- Oxidation states: 0\n- Standard state: Gas\n- Melting point: 0.95 K\n- Boiling point: 4.22 K\n- Density: 0.0001785 g/cm³\n- Chemical group: Noble gas\n- Year discovered: 1868"},{"id":"f1fa4d0a-2e74-43ba-be23-cbc25fc4dd26","title":"Lithium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/3","version":1,"createdAt":"2026-10-04T00:13:16.000Z","updatedAt":"2026-10-04T00:13:16.000Z","text":"Lithium (Li) is chemical element 3, an alkali metal in group 1, period 2 (PubChem).\n\n- Atomic number: 3\n- Symbol: Li\n- Group: 1\n- Period: 2\n- Atomic mass: 7.0 u\n- Electron configuration: [He]2s1\n- Electronegativity (Pauling scale): 0.98\n- Atomic radius (van der Waals): 182 pm\n- Ionization energy: 5.392 eV\n- Electron affinity: 0.618 eV\n- Oxidation states: +1\n- Standard state: Solid\n- Melting point: 453.65 K\n- Boiling point: 1615 K\n- Density: 0.534 g/cm³\n- Chemical group: Alkali metal\n- Year discovered: 1817"},{"id":"ff555568-b4e7-4271-b98a-de8d2a66328b","title":"Beryllium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/4","version":1,"createdAt":"2026-10-04T00:13:22.000Z","updatedAt":"2026-10-04T00:13:22.000Z","text":"Beryllium (Be) is chemical element 4, an alkaline earth metal in group 2, period 2 (PubChem).\n\n- Atomic number: 4\n- Symbol: Be\n- Group: 2\n- Period: 2\n- Atomic mass: 9.012183 u\n- Electron configuration: [He]2s2\n- Electronegativity (Pauling scale): 1.57\n- Atomic radius (van der Waals): 153 pm\n- Ionization energy: 9.323 eV\n- Oxidation states: +2\n- Standard state: Solid\n- Melting point: 1560 K\n- Boiling point: 2744 K\n- Density: 1.85 g/cm³\n- Chemical group: Alkaline earth metal\n- Year discovered: 1798"},{"id":"9ce86fa7-a814-49a5-9d00-80301916e099","title":"Boron","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/5","version":1,"createdAt":"2026-10-04T00:13:29.000Z","updatedAt":"2026-10-04T00:13:29.000Z","text":"Boron (B) is chemical element 5, a metalloid in group 13, period 2 (PubChem).\n\n- Atomic number: 5\n- Symbol: B\n- Group: 13\n- Period: 2\n- Atomic mass: 10.81 u\n- Electron configuration: [He]2s2 2p1\n- Electronegativity (Pauling scale): 2.04\n- Atomic radius (van der Waals): 192 pm\n- Ionization energy: 8.298 eV\n- Electron affinity: 0.277 eV\n- Oxidation states: +3\n- Standard state: Solid\n- Melting point: 2348 K\n- Boiling point: 4273 K\n- Density: 2.37 g/cm³\n- Chemical group: Metalloid\n- Year discovered: 1808"},{"id":"2ae3d6a4-9a4b-44e4-84c2-734ad72fe3e4","title":"Carbon","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/6","version":1,"createdAt":"2026-10-04T00:13:36.000Z","updatedAt":"2026-10-04T00:13:36.000Z","text":"Carbon (C) is chemical element 6, a nonmetal in group 14, period 2 (PubChem).\n\n- Atomic number: 6\n- Symbol: C\n- Group: 14\n- Period: 2\n- Atomic mass: 12.011 u\n- Electron configuration: [He]2s2 2p2\n- Electronegativity (Pauling scale): 2.55\n- Atomic radius (van der Waals): 170 pm\n- Ionization energy: 11.260 eV\n- Electron affinity: 1.263 eV\n- Oxidation states: +4, +2, -4\n- Standard state: Solid\n- Melting point: 3823 K\n- Boiling point: 4098 K\n- Density: 2.2670 g/cm³\n- Chemical group: Nonmetal\n- Year discovered: Ancient"},{"id":"dd497939-a664-4421-9bf0-d070736176ec","title":"Nitrogen","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/7","version":1,"createdAt":"2026-10-04T00:13:42.000Z","updatedAt":"2026-10-04T00:13:42.000Z","text":"Nitrogen (N) is chemical element 7, a nonmetal in group 15, period 2 (PubChem).\n\n- Atomic number: 7\n- Symbol: N\n- Group: 15\n- Period: 2\n- Atomic mass: 14.007 u\n- Electron configuration: [He] 2s2 2p3\n- Electronegativity (Pauling scale): 3.04\n- Atomic radius (van der Waals): 155 pm\n- Ionization energy: 14.534 eV\n- Oxidation states: +5, +4, +3, +2, +1, -1, -2, -3\n- Standard state: Gas\n- Melting point: 63.15 K\n- Boiling point: 77.36 K\n- Density: 0.0012506 g/cm³\n- Chemical group: Nonmetal\n- Year discovered: 1772"},{"id":"21f389f1-db9d-445f-b9e3-0962c0c3fc4e","title":"Oxygen","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/8","version":1,"createdAt":"2026-10-04T00:13:49.000Z","updatedAt":"2026-10-04T00:13:49.000Z","text":"Oxygen (O) is chemical element 8, a nonmetal in group 16, period 2 (PubChem).\n\n- Atomic number: 8\n- Symbol: O\n- Group: 16\n- Period: 2\n- Atomic mass: 15.999 u\n- Electron configuration: [He]2s2 2p4\n- Electronegativity (Pauling scale): 3.44\n- Atomic radius (van der Waals): 152 pm\n- Ionization energy: 13.618 eV\n- Electron affinity: 1.461 eV\n- Oxidation states: -2\n- Standard state: Gas\n- Melting point: 54.36 K\n- Boiling point: 90.2 K\n- Density: 0.001429 g/cm³\n- Chemical group: Nonmetal\n- Year discovered: 1774"},{"id":"f5470870-e7da-4697-b401-9fb7fd32e1e6","title":"Fluorine","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/9","version":1,"createdAt":"2026-10-04T00:13:56.000Z","updatedAt":"2026-10-04T00:13:56.000Z","text":"Fluorine (F) is chemical element 9, a halogen in group 17, period 2 (PubChem).\n\n- Atomic number: 9\n- Symbol: F\n- Group: 17\n- Period: 2\n- Atomic mass: 18.99840316 u\n- Electron configuration: [He]2s2 2p5\n- Electronegativity (Pauling scale): 3.98\n- Atomic radius (van der Waals): 135 pm\n- Ionization energy: 17.423 eV\n- Electron affinity: 3.339 eV\n- Oxidation states: -1\n- Standard state: Gas\n- Melting point: 53.53 K\n- Boiling point: 85.03 K\n- Density: 0.001696 g/cm³\n- Chemical group: Halogen\n- Year discovered: 1670"},{"id":"dc54182b-fabc-4c39-b376-48c769a685c4","title":"Neon","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/10","version":1,"createdAt":"2026-10-04T00:14:02.000Z","updatedAt":"2026-10-04T00:14:02.000Z","text":"Neon (Ne) is chemical element 10, a noble gas in group 18, period 2 (PubChem).\n\n- Atomic number: 10\n- Symbol: Ne\n- Group: 18\n- Period: 2\n- Atomic mass: 20.180 u\n- Electron configuration: [He]2s2 2p6\n- Atomic radius (van der Waals): 154 pm\n- Ionization energy: 21.565 eV\n- Oxidation states: 0\n- Standard state: Gas\n- Melting point: 24.56 K\n- Boiling point: 27.07 K\n- Density: 0.0008999 g/cm³\n- Chemical group: Noble gas\n- Year discovered: 1898"},{"id":"e9bb3646-48c0-4cb1-9a16-1b567a488d22","title":"Sodium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/11","version":1,"createdAt":"2026-10-04T00:14:09.000Z","updatedAt":"2026-10-04T00:14:09.000Z","text":"Sodium (Na) is chemical element 11, an alkali metal in group 1, period 3 (PubChem).\n\n- Atomic number: 11\n- Symbol: Na\n- Group: 1\n- Period: 3\n- Atomic mass: 22.9897693 u\n- Electron configuration: [Ne]3s1\n- Electronegativity (Pauling scale): 0.93\n- Atomic radius (van der Waals): 227 pm\n- Ionization energy: 5.139 eV\n- Electron affinity: 0.548 eV\n- Oxidation states: +1\n- Standard state: Solid\n- Melting point: 370.95 K\n- Boiling point: 1156 K\n- Density: 0.97 g/cm³\n- Chemical group: Alkali metal\n- Year discovered: 1807"},{"id":"db4c3dc2-f665-4952-935c-ce45a35f3036","title":"Magnesium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/12","version":1,"createdAt":"2026-10-04T00:14:16.000Z","updatedAt":"2026-10-04T00:14:16.000Z","text":"Magnesium (Mg) is chemical element 12, an alkaline earth metal in group 2, period 3 (PubChem).\n\n- Atomic number: 12\n- Symbol: Mg\n- Group: 2\n- Period: 3\n- Atomic mass: 24.305 u\n- Electron configuration: [Ne]3s2\n- Electronegativity (Pauling scale): 1.31\n- Atomic radius (van der Waals): 173 pm\n- Ionization energy: 7.646 eV\n- Oxidation states: +2\n- Standard state: Solid\n- Melting point: 923 K\n- Boiling point: 1363 K\n- Density: 1.74 g/cm³\n- Chemical group: Alkaline earth metal\n- Year discovered: 1808"},{"id":"605f3b4a-a763-47ee-becf-9f22ab9472e7","title":"Aluminum","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/13","version":1,"createdAt":"2026-10-04T00:14:22.000Z","updatedAt":"2026-10-04T00:14:22.000Z","text":"Aluminum (Al) is chemical element 13, a post-transition metal in group 13, period 3 (PubChem).\n\n- Atomic number: 13\n- Symbol: Al\n- Group: 13\n- Period: 3\n- Atomic mass: 26.981538 u\n- Electron configuration: [Ne]3s2 3p1\n- Electronegativity (Pauling scale): 1.61\n- Atomic radius (van der Waals): 184 pm\n- Ionization energy: 5.986 eV\n- Electron affinity: 0.441 eV\n- Oxidation states: +3\n- Standard state: Solid\n- Melting point: 933.437 K\n- Boiling point: 2792 K\n- Density: 2.70 g/cm³\n- Chemical group: Post-transition metal\n- Year discovered: Ancient"},{"id":"ea5b005e-5863-4f34-ada6-5e1d5057d22a","title":"Silicon","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/14","version":1,"createdAt":"2026-10-04T00:14:29.000Z","updatedAt":"2026-10-04T00:14:29.000Z","text":"Silicon (Si) is chemical element 14, a metalloid in group 14, period 3 (PubChem).\n\n- Atomic number: 14\n- Symbol: Si\n- Group: 14\n- Period: 3\n- Atomic mass: 28.085 u\n- Electron configuration: [Ne]3s2 3p2\n- Electronegativity (Pauling scale): 1.9\n- Atomic radius (van der Waals): 210 pm\n- Ionization energy: 8.152 eV\n- Electron affinity: 1.385 eV\n- Oxidation states: +4, +2, -4\n- Standard state: Solid\n- Melting point: 1687 K\n- Boiling point: 3538 K\n- Density: 2.3296 g/cm³\n- Chemical group: Metalloid\n- Year discovered: 1854"},{"id":"6efb7e3c-c885-4fa4-8501-9c4b07f9942d","title":"Phosphorus","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/15","version":1,"createdAt":"2026-10-04T00:14:36.000Z","updatedAt":"2026-10-04T00:14:36.000Z","text":"Phosphorus (P) is chemical element 15, a nonmetal in group 15, period 3 (PubChem).\n\n- Atomic number: 15\n- Symbol: P\n- Group: 15\n- Period: 3\n- Atomic mass: 30.97376200 u\n- Electron configuration: [Ne]3s2 3p3\n- Electronegativity (Pauling scale): 2.19\n- Atomic radius (van der Waals): 180 pm\n- Ionization energy: 10.487 eV\n- Electron affinity: 0.746 eV\n- Oxidation states: +5, +3, -3\n- Standard state: Solid\n- Melting point: 317.3 K\n- Boiling point: 553.65 K\n- Density: 1.82 g/cm³\n- Chemical group: Nonmetal\n- Year discovered: 1669"},{"id":"0570e7f2-2f52-436e-942b-0d167c8fdb09","title":"Sulfur","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/16","version":1,"createdAt":"2026-10-04T00:14:42.000Z","updatedAt":"2026-10-04T00:14:42.000Z","text":"Sulfur (S) is chemical element 16, a nonmetal in group 16, period 3 (PubChem).\n\n- Atomic number: 16\n- Symbol: S\n- Group: 16\n- Period: 3\n- Atomic mass: 32.07 u\n- Electron configuration: [Ne]3s2 3p4\n- Electronegativity (Pauling scale): 2.58\n- Atomic radius (van der Waals): 180 pm\n- Ionization energy: 10.360 eV\n- Electron affinity: 2.077 eV\n- Oxidation states: +6, +4, -2\n- Standard state: Solid\n- Melting point: 388.36 K\n- Boiling point: 717.75 K\n- Density: 2.067 g/cm³\n- Chemical group: Nonmetal\n- Year discovered: Ancient"},{"id":"9b89fda3-e880-41d3-a09c-bc52627349ba","title":"Chlorine","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/17","version":1,"createdAt":"2026-10-04T00:14:49.000Z","updatedAt":"2026-10-04T00:14:49.000Z","text":"Chlorine (Cl) is chemical element 17, a halogen in group 17, period 3 (PubChem).\n\n- Atomic number: 17\n- Symbol: Cl\n- Group: 17\n- Period: 3\n- Atomic mass: 35.45 u\n- Electron configuration: [Ne]3s2 3p5\n- Electronegativity (Pauling scale): 3.16\n- Atomic radius (van der Waals): 175 pm\n- Ionization energy: 12.968 eV\n- Electron affinity: 3.617 eV\n- Oxidation states: +7, +5, +1, -1\n- Standard state: Gas\n- Melting point: 171.65 K\n- Boiling point: 239.11 K\n- Density: 0.003214 g/cm³\n- Chemical group: Halogen\n- Year discovered: 1774"},{"id":"03214ecb-045c-46d4-83ba-7e82b856020d","title":"Argon","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/18","version":1,"createdAt":"2026-10-04T00:14:56.000Z","updatedAt":"2026-10-04T00:14:56.000Z","text":"Argon (Ar) is chemical element 18, a noble gas in group 18, period 3 (PubChem).\n\n- Atomic number: 18\n- Symbol: Ar\n- Group: 18\n- Period: 3\n- Atomic mass: 39.9 u\n- Electron configuration: [Ne]3s2 3p6\n- Atomic radius (van der Waals): 188 pm\n- Ionization energy: 15.760 eV\n- Oxidation states: 0\n- Standard state: Gas\n- Melting point: 83.8 K\n- Boiling point: 87.3 K\n- Density: 0.0017837 g/cm³\n- Chemical group: Noble gas\n- Year discovered: 1894"},{"id":"8ad59839-0bb1-4fe5-b0a6-de479741fd3f","title":"Potassium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/19","version":1,"createdAt":"2026-10-04T00:15:02.000Z","updatedAt":"2026-10-04T00:15:02.000Z","text":"Potassium (K) is chemical element 19, an alkali metal in group 1, period 4 (PubChem).\n\n- Atomic number: 19\n- Symbol: K\n- Group: 1\n- Period: 4\n- Atomic mass: 39.0983 u\n- Electron configuration: [Ar]4s1\n- Electronegativity (Pauling scale): 0.82\n- Atomic radius (van der Waals): 275 pm\n- Ionization energy: 4.341 eV\n- Electron affinity: 0.501 eV\n- Oxidation states: +1\n- Standard state: Solid\n- Melting point: 336.53 K\n- Boiling point: 1032 K\n- Density: 0.89 g/cm³\n- Chemical group: Alkali metal\n- Year discovered: 1807"},{"id":"719c4839-1bed-4423-a664-0d2c63f0bb4b","title":"Calcium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/20","version":1,"createdAt":"2026-10-04T00:15:09.000Z","updatedAt":"2026-10-04T00:15:09.000Z","text":"Calcium (Ca) is chemical element 20, an alkaline earth metal in group 2, period 4 (PubChem).\n\n- Atomic number: 20\n- Symbol: Ca\n- Group: 2\n- Period: 4\n- Atomic mass: 40.08 u\n- Electron configuration: [Ar]4s2\n- Electronegativity (Pauling scale): 1\n- Atomic radius (van der Waals): 231 pm\n- Ionization energy: 6.113 eV\n- Oxidation states: +2\n- Standard state: Solid\n- Melting point: 1115 K\n- Boiling point: 1757 K\n- Density: 1.54 g/cm³\n- Chemical group: Alkaline earth metal\n- Year discovered: Ancient"},{"id":"a691ee24-6060-4c35-85bf-916fe9f9d7db","title":"Scandium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/21","version":1,"createdAt":"2026-10-04T00:15:16.000Z","updatedAt":"2026-10-04T00:15:16.000Z","text":"Scandium (Sc) is chemical element 21, a transition metal in group 3, period 4 (PubChem).\n\n- Atomic number: 21\n- Symbol: Sc\n- Group: 3\n- Period: 4\n- Atomic mass: 44.95591 u\n- Electron configuration: [Ar]4s2 3d1\n- Electronegativity (Pauling scale): 1.36\n- Atomic radius (van der Waals): 211 pm\n- Ionization energy: 6.561 eV\n- Electron affinity: 0.188 eV\n- Oxidation states: +3\n- Standard state: Solid\n- Melting point: 1814 K\n- Boiling point: 3109 K\n- Density: 2.99 g/cm³\n- Chemical group: Transition metal\n- Year discovered: 1879"},{"id":"fd56688b-d21f-42ff-b21d-180cd5ade3a9","title":"Titanium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/22","version":1,"createdAt":"2026-10-04T00:15:22.000Z","updatedAt":"2026-10-04T00:15:22.000Z","text":"Titanium (Ti) is chemical element 22, a transition metal in group 4, period 4 (PubChem).\n\n- Atomic number: 22\n- Symbol: Ti\n- Group: 4\n- Period: 4\n- Atomic mass: 47.867 u\n- Electron configuration: [Ar]4s2 3d2\n- Electronegativity (Pauling scale): 1.54\n- Atomic radius (van der Waals): 187 pm\n- Ionization energy: 6.828 eV\n- Electron affinity: 0.079 eV\n- Oxidation states: +4, +3, +2\n- Standard state: Solid\n- Melting point: 1941 K\n- Boiling point: 3560 K\n- Density: 4.5 g/cm³\n- Chemical group: Transition metal\n- Year discovered: 1791"},{"id":"c70b1a20-8eb2-4064-a401-a4c292a9154a","title":"Vanadium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/23","version":1,"createdAt":"2026-10-04T00:15:29.000Z","updatedAt":"2026-10-04T00:15:29.000Z","text":"Vanadium (V) is chemical element 23, a transition metal in group 5, period 4 (PubChem).\n\n- Atomic number: 23\n- Symbol: V\n- Group: 5\n- Period: 4\n- Atomic mass: 50.9415 u\n- Electron configuration: [Ar]4s2 3d3\n- Electronegativity (Pauling scale): 1.63\n- Atomic radius (van der Waals): 179 pm\n- Ionization energy: 6.746 eV\n- Electron affinity: 0.525 eV\n- Oxidation states: +5, +4, +3, +2\n- Standard state: Solid\n- Melting point: 2183 K\n- Boiling point: 3680 K\n- Density: 6.0 g/cm³\n- Chemical group: Transition metal\n- Year discovered: 1801"},{"id":"f98c811b-2264-4961-9f67-2e20ef423443","title":"Chromium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/24","version":1,"createdAt":"2026-10-04T00:15:36.000Z","updatedAt":"2026-10-04T00:15:36.000Z","text":"Chromium (Cr) is chemical element 24, a transition metal in group 6, period 4 (PubChem).\n\n- Atomic number: 24\n- Symbol: Cr\n- Group: 6\n- Period: 4\n- Atomic mass: 51.996 u\n- Electron configuration: [Ar]3d5 4s1\n- Electronegativity (Pauling scale): 1.66\n- Atomic radius (van der Waals): 189 pm\n- Ionization energy: 6.767 eV\n- Electron affinity: 0.666 eV\n- Oxidation states: +6, +3, +2\n- Standard state: Solid\n- Melting point: 2180 K\n- Boiling point: 2944 K\n- Density: 7.15 g/cm³\n- Chemical group: Transition metal\n- Year discovered: 1797"},{"id":"56db62fd-da3f-46be-bd3e-8ac126545f1e","title":"Manganese","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/25","version":1,"createdAt":"2026-10-04T00:15:42.000Z","updatedAt":"2026-10-04T00:15:42.000Z","text":"Manganese (Mn) is chemical element 25, a transition metal in group 7, period 4 (PubChem).\n\n- Atomic number: 25\n- Symbol: Mn\n- Group: 7\n- Period: 4\n- Atomic mass: 54.93804 u\n- Electron configuration: [Ar]4s2 3d5\n- Electronegativity (Pauling scale): 1.55\n- Atomic radius (van der Waals): 197 pm\n- Ionization energy: 7.434 eV\n- Oxidation states: +7, +4, +3, +2\n- Standard state: Solid\n- Melting point: 1519 K\n- Boiling point: 2334 K\n- Density: 7.3 g/cm³\n- Chemical group: Transition metal\n- Year discovered: 1774"},{"id":"96a0a60f-1190-4331-861d-44331c601fbd","title":"Iron","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/26","version":1,"createdAt":"2026-10-04T00:15:49.000Z","updatedAt":"2026-10-04T00:15:49.000Z","text":"Iron (Fe) is chemical element 26, a transition metal in group 8, period 4 (PubChem).\n\n- Atomic number: 26\n- Symbol: Fe\n- Group: 8\n- Period: 4\n- Atomic mass: 55.84 u\n- Electron configuration: [Ar]4s2 3d6\n- Electronegativity (Pauling scale): 1.83\n- Atomic radius (van der Waals): 194 pm\n- Ionization energy: 7.902 eV\n- Electron affinity: 0.163 eV\n- Oxidation states: +3, +2\n- Standard state: Solid\n- Melting point: 1811 K\n- Boiling point: 3134 K\n- Density: 7.874 g/cm³\n- Chemical group: Transition metal\n- Year discovered: Ancient"},{"id":"66cde7a7-6b5a-4546-b750-12bb433e8076","title":"Cobalt","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/27","version":1,"createdAt":"2026-10-04T00:15:56.000Z","updatedAt":"2026-10-04T00:15:56.000Z","text":"Cobalt (Co) is chemical element 27, a transition metal in group 9, period 4 (PubChem).\n\n- Atomic number: 27\n- Symbol: Co\n- Group: 9\n- Period: 4\n- Atomic mass: 58.93319 u\n- Electron configuration: [Ar]4s2 3d7\n- Electronegativity (Pauling scale): 1.88\n- Atomic radius (van der Waals): 192 pm\n- Ionization energy: 7.881 eV\n- Electron affinity: 0.661 eV\n- Oxidation states: +3, +2\n- Standard state: Solid\n- Melting point: 1768 K\n- Boiling point: 3200 K\n- Density: 8.86 g/cm³\n- Chemical group: Transition metal\n- Year discovered: 1735"},{"id":"cde59997-bfc1-4f28-92ea-f0df0405da5b","title":"Nickel","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/28","version":1,"createdAt":"2026-10-04T00:16:02.000Z","updatedAt":"2026-10-04T00:16:02.000Z","text":"Nickel (Ni) is chemical element 28, a transition metal in group 10, period 4 (PubChem).\n\n- Atomic number: 28\n- Symbol: Ni\n- Group: 10\n- Period: 4\n- Atomic mass: 58.693 u\n- Electron configuration: [Ar]4s2 3d8\n- Electronegativity (Pauling scale): 1.91\n- Atomic radius (van der Waals): 163 pm\n- Ionization energy: 7.640 eV\n- Electron affinity: 1.156 eV\n- Oxidation states: +3, +2\n- Standard state: Solid\n- Melting point: 1728 K\n- Boiling point: 3186 K\n- Density: 8.912 g/cm³\n- Chemical group: Transition metal\n- Year discovered: 1751"},{"id":"254b8639-4831-45c6-9889-8329082ff407","title":"Copper","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/29","version":1,"createdAt":"2026-10-04T00:16:09.000Z","updatedAt":"2026-10-04T00:16:09.000Z","text":"Copper (Cu) is chemical element 29, a transition metal in group 11, period 4 (PubChem).\n\n- Atomic number: 29\n- Symbol: Cu\n- Group: 11\n- Period: 4\n- Atomic mass: 63.55 u\n- Electron configuration: [Ar]4s1 3d10\n- Electronegativity (Pauling scale): 1.9\n- Atomic radius (van der Waals): 140 pm\n- Ionization energy: 7.726 eV\n- Electron affinity: 1.228 eV\n- Oxidation states: +2, +1\n- Standard state: Solid\n- Melting point: 1357.77 K\n- Boiling point: 2835 K\n- Density: 8.933 g/cm³\n- Chemical group: Transition metal\n- Year discovered: Ancient"},{"id":"a01523c3-7bf3-47a2-be32-6c45c60fd487","title":"Zinc","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/30","version":1,"createdAt":"2026-10-04T00:16:16.000Z","updatedAt":"2026-10-04T00:16:16.000Z","text":"Zinc (Zn) is chemical element 30, a transition metal in group 12, period 4 (PubChem).\n\n- Atomic number: 30\n- Symbol: Zn\n- Group: 12\n- Period: 4\n- Atomic mass: 65.4 u\n- Electron configuration: [Ar]4s2 3d10\n- Electronegativity (Pauling scale): 1.65\n- Atomic radius (van der Waals): 139 pm\n- Ionization energy: 9.394 eV\n- Oxidation states: +2\n- Standard state: Solid\n- Melting point: 692.68 K\n- Boiling point: 1180 K\n- Density: 7.134 g/cm³\n- Chemical group: Transition metal\n- Year discovered: 1746"},{"id":"6a02c49b-bb97-40e9-a066-44b38d1302b7","title":"Gallium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/31","version":1,"createdAt":"2026-10-04T00:16:22.000Z","updatedAt":"2026-10-04T00:16:22.000Z","text":"Gallium (Ga) is chemical element 31, a post-transition metal in group 13, period 4 (PubChem).\n\n- Atomic number: 31\n- Symbol: Ga\n- Group: 13\n- Period: 4\n- Atomic mass: 69.723 u\n- Electron configuration: [Ar]4s2 3d10 4p1\n- Electronegativity (Pauling scale): 1.81\n- Atomic radius (van der Waals): 187 pm\n- Ionization energy: 5.999 eV\n- Electron affinity: 0.3 eV\n- Oxidation states: +3\n- Standard state: Solid\n- Melting point: 302.91 K\n- Boiling point: 2477 K\n- Density: 5.91 g/cm³\n- Chemical group: Post-transition metal\n- Year discovered: 1875"},{"id":"bf1280bd-f8f5-4f7d-8f8c-ac705e2b0bd3","title":"Germanium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/32","version":1,"createdAt":"2026-10-04T00:16:29.000Z","updatedAt":"2026-10-04T00:16:29.000Z","text":"Germanium (Ge) is chemical element 32, a metalloid in group 14, period 4 (PubChem).\n\n- Atomic number: 32\n- Symbol: Ge\n- Group: 14\n- Period: 4\n- Atomic mass: 72.63 u\n- Electron configuration: [Ar]4s2 3d10 4p2\n- Electronegativity (Pauling scale): 2.01\n- Atomic radius (van der Waals): 211 pm\n- Ionization energy: 7.900 eV\n- Electron affinity: 1.35 eV\n- Oxidation states: +4, +2\n- Standard state: Solid\n- Melting point: 1211.4 K\n- Boiling point: 3106 K\n- Density: 5.323 g/cm³\n- Chemical group: Metalloid\n- Year discovered: 1886"},{"id":"b70f631a-faca-4e51-b84c-c395c6a0a87f","title":"Arsenic","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/33","version":1,"createdAt":"2026-10-04T00:16:36.000Z","updatedAt":"2026-10-04T00:16:36.000Z","text":"Arsenic (As) is chemical element 33, a metalloid in group 15, period 4 (PubChem).\n\n- Atomic number: 33\n- Symbol: As\n- Group: 15\n- Period: 4\n- Atomic mass: 74.92159 u\n- Electron configuration: [Ar]4s2 3d10 4p3\n- Electronegativity (Pauling scale): 2.18\n- Atomic radius (van der Waals): 185 pm\n- Ionization energy: 9.815 eV\n- Electron affinity: 0.81 eV\n- Oxidation states: +5, +3, -3\n- Standard state: Solid\n- Melting point: 1090 K\n- Boiling point: 887 K\n- Density: 5.776 g/cm³\n- Chemical group: Metalloid\n- Year discovered: Ancient"},{"id":"c50d1c9e-2b2c-4cb5-94ce-691f294dcfda","title":"Selenium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/34","version":1,"createdAt":"2026-10-04T00:16:42.000Z","updatedAt":"2026-10-04T00:16:42.000Z","text":"Selenium (Se) is chemical element 34, a nonmetal in group 16, period 4 (PubChem).\n\n- Atomic number: 34\n- Symbol: Se\n- Group: 16\n- Period: 4\n- Atomic mass: 78.97 u\n- Electron configuration: [Ar]4s2 3d10 4p4\n- Electronegativity (Pauling scale): 2.55\n- Atomic radius (van der Waals): 190 pm\n- Ionization energy: 9.752 eV\n- Electron affinity: 2.021 eV\n- Oxidation states: +6, +4, -2\n- Standard state: Solid\n- Melting point: 493.65 K\n- Boiling point: 958 K\n- Density: 4.809 g/cm³\n- Chemical group: Nonmetal\n- Year discovered: 1817"},{"id":"5d9f75a7-f087-4ea6-ae13-a39c3e292e8a","title":"Bromine","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/35","version":1,"createdAt":"2026-10-04T00:16:49.000Z","updatedAt":"2026-10-04T00:16:49.000Z","text":"Bromine (Br) is chemical element 35, a halogen in group 17, period 4 (PubChem).\n\n- Atomic number: 35\n- Symbol: Br\n- Group: 17\n- Period: 4\n- Atomic mass: 79.90 u\n- Electron configuration: [Ar]4s2 3d10 4p5\n- Electronegativity (Pauling scale): 2.96\n- Atomic radius (van der Waals): 183 pm\n- Ionization energy: 11.814 eV\n- Electron affinity: 3.365 eV\n- Oxidation states: +5, +1, -1\n- Standard state: Liquid\n- Melting point: 265.95 K\n- Boiling point: 331.95 K\n- Density: 3.11 g/cm³\n- Chemical group: Halogen\n- Year discovered: 1826"},{"id":"693c3a55-a183-4024-be2e-abdfb00bf4bd","title":"Krypton","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/36","version":1,"createdAt":"2026-10-04T00:16:56.000Z","updatedAt":"2026-10-04T00:16:56.000Z","text":"Krypton (Kr) is chemical element 36, a noble gas in group 18, period 4 (PubChem).\n\n- Atomic number: 36\n- Symbol: Kr\n- Group: 18\n- Period: 4\n- Atomic mass: 83.80 u\n- Electron configuration: [Ar]4s2 3d10 4p6\n- Electronegativity (Pauling scale): 3\n- Atomic radius (van der Waals): 202 pm\n- Ionization energy: 14.000 eV\n- Oxidation states: 0\n- Standard state: Gas\n- Melting point: 115.79 K\n- Boiling point: 119.93 K\n- Density: 0.003733 g/cm³\n- Chemical group: Noble gas\n- Year discovered: 1898"},{"id":"0e7038ec-9e8d-4477-b207-753e547858b6","title":"Rubidium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/37","version":1,"createdAt":"2026-10-04T00:17:02.000Z","updatedAt":"2026-10-04T00:17:02.000Z","text":"Rubidium (Rb) is chemical element 37, an alkali metal in group 1, period 5 (PubChem).\n\n- Atomic number: 37\n- Symbol: Rb\n- Group: 1\n- Period: 5\n- Atomic mass: 85.468 u\n- Electron configuration: [Kr]5s1\n- Electronegativity (Pauling scale): 0.82\n- Atomic radius (van der Waals): 303 pm\n- Ionization energy: 4.177 eV\n- Electron affinity: 0.468 eV\n- Oxidation states: +1\n- Standard state: Solid\n- Melting point: 312.46 K\n- Boiling point: 961 K\n- Density: 1.53 g/cm³\n- Chemical group: Alkali metal\n- Year discovered: 1861"},{"id":"f314f6df-4e2d-4efe-9b0a-f2e328c20045","title":"Strontium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/38","version":1,"createdAt":"2026-10-04T00:17:09.000Z","updatedAt":"2026-10-04T00:17:09.000Z","text":"Strontium (Sr) is chemical element 38, an alkaline earth metal in group 2, period 5 (PubChem).\n\n- Atomic number: 38\n- Symbol: Sr\n- Group: 2\n- Period: 5\n- Atomic mass: 87.62 u\n- Electron configuration: [Kr]5s2\n- Electronegativity (Pauling scale): 0.95\n- Atomic radius (van der Waals): 249 pm\n- Ionization energy: 5.695 eV\n- Oxidation states: +2\n- Standard state: Solid\n- Melting point: 1050 K\n- Boiling point: 1655 K\n- Density: 2.64 g/cm³\n- Chemical group: Alkaline earth metal\n- Year discovered: 1790"},{"id":"90f1980f-c4fc-48b6-a4cb-1f096ad43b61","title":"Yttrium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/39","version":1,"createdAt":"2026-10-04T00:17:16.000Z","updatedAt":"2026-10-04T00:17:16.000Z","text":"Yttrium (Y) is chemical element 39, a transition metal in group 3, period 5 (PubChem).\n\n- Atomic number: 39\n- Symbol: Y\n- Group: 3\n- Period: 5\n- Atomic mass: 88.90584 u\n- Electron configuration: [Kr]5s2 4d1\n- Electronegativity (Pauling scale): 1.22\n- Atomic radius (van der Waals): 219 pm\n- Ionization energy: 6.217 eV\n- Electron affinity: 0.307 eV\n- Oxidation states: +3\n- Standard state: Solid\n- Melting point: 1795 K\n- Boiling point: 3618 K\n- Density: 4.47 g/cm³\n- Chemical group: Transition metal\n- Year discovered: 1794"},{"id":"f0318d59-4dc7-400d-8041-8280ba961884","title":"Zirconium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/40","version":1,"createdAt":"2026-10-04T00:17:22.000Z","updatedAt":"2026-10-04T00:17:23.000Z","text":"Zirconium (Zr) is chemical element 40, a transition metal in group 4, period 5 (PubChem).\n\n- Atomic number: 40\n- Symbol: Zr\n- Group: 4\n- Period: 5\n- Atomic mass: 91.22 u\n- Electron configuration: [Kr]5s2 4d2\n- Electronegativity (Pauling scale): 1.33\n- Atomic radius (van der Waals): 186 pm\n- Ionization energy: 6.634 eV\n- Electron affinity: 0.426 eV\n- Oxidation states: +4\n- Standard state: Solid\n- Melting point: 2128 K\n- Boiling point: 4682 K\n- Density: 6.52 g/cm³\n- Chemical group: Transition metal\n- Year discovered: 1789"},{"id":"7111c9fc-d69b-45c8-a735-a812c7448df1","title":"Niobium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/41","version":1,"createdAt":"2026-10-04T00:17:29.000Z","updatedAt":"2026-10-04T00:17:29.000Z","text":"Niobium (Nb) is chemical element 41, a transition metal in group 5, period 5 (PubChem).\n\n- Atomic number: 41\n- Symbol: Nb\n- Group: 5\n- Period: 5\n- Atomic mass: 92.90637 u\n- Electron configuration: [Kr]5s1 4d4\n- Electronegativity (Pauling scale): 1.6\n- Atomic radius (van der Waals): 207 pm\n- Ionization energy: 6.759 eV\n- Electron affinity: 0.893 eV\n- Oxidation states: +5, +3\n- Standard state: Solid\n- Melting point: 2750 K\n- Boiling point: 5017 K\n- Density: 8.57 g/cm³\n- Chemical group: Transition metal\n- Year discovered: 1801"},{"id":"fa17d9d8-02df-420c-8155-46265e87d133","title":"Molybdenum","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/42","version":1,"createdAt":"2026-10-04T00:17:36.000Z","updatedAt":"2026-10-04T00:17:36.000Z","text":"Molybdenum (Mo) is chemical element 42, a transition metal in group 6, period 5 (PubChem).\n\n- Atomic number: 42\n- Symbol: Mo\n- Group: 6\n- Period: 5\n- Atomic mass: 95.95 u\n- Electron configuration: [Kr]5s1 4d5\n- Electronegativity (Pauling scale): 2.16\n- Atomic radius (van der Waals): 209 pm\n- Ionization energy: 7.092 eV\n- Electron affinity: 0.746 eV\n- Oxidation states: +6\n- Standard state: Solid\n- Melting point: 2896 K\n- Boiling point: 4912 K\n- Density: 10.2 g/cm³\n- Chemical group: Transition metal\n- Year discovered: 1778"},{"id":"51c4c638-62d7-4d9c-9749-0bf8378cb85d","title":"Technetium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/43","version":1,"createdAt":"2026-10-04T00:17:43.000Z","updatedAt":"2026-10-04T00:17:43.000Z","text":"Technetium (Tc) is chemical element 43, a transition metal in group 7, period 5 (PubChem).\n\n- Atomic number: 43\n- Symbol: Tc\n- Group: 7\n- Period: 5\n- Atomic mass: 96.90636 u\n- Electron configuration: [Kr]5s2 4d5\n- Electronegativity (Pauling scale): 1.9\n- Atomic radius (van der Waals): 209 pm\n- Ionization energy: 7.28 eV\n- Electron affinity: 0.55 eV\n- Oxidation states: +7, +6, +4\n- Standard state: Solid\n- Melting point: 2430 K\n- Boiling point: 4538 K\n- Density: 11 g/cm³\n- Chemical group: Transition metal\n- Year discovered: 1937"},{"id":"d846090e-a92a-4526-995e-927cd2a8587f","title":"Ruthenium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/44","version":1,"createdAt":"2026-10-04T00:17:49.000Z","updatedAt":"2026-10-04T00:17:49.000Z","text":"Ruthenium (Ru) is chemical element 44, a transition metal in group 8, period 5 (PubChem).\n\n- Atomic number: 44\n- Symbol: Ru\n- Group: 8\n- Period: 5\n- Atomic mass: 101.1 u\n- Electron configuration: [Kr]5s1 4d7\n- Electronegativity (Pauling scale): 2.2\n- Atomic radius (van der Waals): 207 pm\n- Ionization energy: 7.361 eV\n- Electron affinity: 1.05 eV\n- Oxidation states: +3\n- Standard state: Solid\n- Melting point: 2607 K\n- Boiling point: 4423 K\n- Density: 12.1 g/cm³\n- Chemical group: Transition metal\n- Year discovered: 1827"},{"id":"886ca792-59d9-44a8-bdb2-c334ca8fb98e","title":"Rhodium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/45","version":1,"createdAt":"2026-10-04T00:17:56.000Z","updatedAt":"2026-10-04T00:17:56.000Z","text":"Rhodium (Rh) is chemical element 45, a transition metal in group 9, period 5 (PubChem).\n\n- Atomic number: 45\n- Symbol: Rh\n- Group: 9\n- Period: 5\n- Atomic mass: 102.9055 u\n- Electron configuration: [Kr]5s1 4d8\n- Electronegativity (Pauling scale): 2.28\n- Atomic radius (van der Waals): 195 pm\n- Ionization energy: 7.459 eV\n- Electron affinity: 1.137 eV\n- Oxidation states: +3\n- Standard state: Solid\n- Melting point: 2237 K\n- Boiling point: 3968 K\n- Density: 12.4 g/cm³\n- Chemical group: Transition metal\n- Year discovered: 1803"},{"id":"3e176785-36d2-4e98-8bde-256c0993a942","title":"Palladium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/46","version":1,"createdAt":"2026-10-04T00:18:03.000Z","updatedAt":"2026-10-04T00:18:03.000Z","text":"Palladium (Pd) is chemical element 46, a transition metal in group 10, period 5 (PubChem).\n\n- Atomic number: 46\n- Symbol: Pd\n- Group: 10\n- Period: 5\n- Atomic mass: 106.42 u\n- Electron configuration: [Kr]4d10\n- Electronegativity (Pauling scale): 2.2\n- Atomic radius (van der Waals): 202 pm\n- Ionization energy: 8.337 eV\n- Electron affinity: 0.557 eV\n- Oxidation states: +3, +2\n- Standard state: Solid\n- Melting point: 1828.05 K\n- Boiling point: 3236 K\n- Density: 12.0 g/cm³\n- Chemical group: Transition metal\n- Year discovered: 1803"},{"id":"11e81e6b-e577-4b12-b9d8-27dcf5501d97","title":"Silver","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/47","version":1,"createdAt":"2026-10-04T00:18:09.000Z","updatedAt":"2026-10-04T00:18:09.000Z","text":"Silver (Ag) is chemical element 47, a transition metal in group 11, period 5 (PubChem).\n\n- Atomic number: 47\n- Symbol: Ag\n- Group: 11\n- Period: 5\n- Atomic mass: 107.868 u\n- Electron configuration: [Kr]5s1 4d10\n- Electronegativity (Pauling scale): 1.93\n- Atomic radius (van der Waals): 172 pm\n- Ionization energy: 7.576 eV\n- Electron affinity: 1.302 eV\n- Oxidation states: +1\n- Standard state: Solid\n- Melting point: 1234.93 K\n- Boiling point: 2435 K\n- Density: 10.501 g/cm³\n- Chemical group: Transition metal\n- Year discovered: Ancient"},{"id":"17d0bd38-8c06-4423-a014-4e10d760f200","title":"Cadmium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/48","version":1,"createdAt":"2026-10-04T00:18:16.000Z","updatedAt":"2026-10-04T00:18:16.000Z","text":"Cadmium (Cd) is chemical element 48, a transition metal in group 12, period 5 (PubChem).\n\n- Atomic number: 48\n- Symbol: Cd\n- Group: 12\n- Period: 5\n- Atomic mass: 112.41 u\n- Electron configuration: [Kr]5s2 4d10\n- Electronegativity (Pauling scale): 1.69\n- Atomic radius (van der Waals): 158 pm\n- Ionization energy: 8.994 eV\n- Oxidation states: +2\n- Standard state: Solid\n- Melting point: 594.22 K\n- Boiling point: 1040 K\n- Density: 8.69 g/cm³\n- Chemical group: Transition metal\n- Year discovered: 1817"},{"id":"c2d99479-1d37-455e-9463-5a71c5bfc7d9","title":"Indium","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/49","version":1,"createdAt":"2026-10-04T00:18:23.000Z","updatedAt":"2026-10-04T00:18:23.000Z","text":"Indium (In) is chemical element 49, a post-transition metal in group 13, period 5 (PubChem).\n\n- Atomic number: 49\n- Symbol: In\n- Group: 13\n- Period: 5\n- Atomic mass: 114.818 u\n- Electron configuration: [Kr]5s2 4d10 5p1\n- Electronegativity (Pauling scale): 1.78\n- Atomic radius (van der Waals): 193 pm\n- Ionization energy: 5.786 eV\n- Electron affinity: 0.3 eV\n- Oxidation states: +3\n- Standard state: Solid\n- Melting point: 429.75 K\n- Boiling point: 2345 K\n- Density: 7.31 g/cm³\n- Chemical group: Post-transition metal\n- Year discovered: 1863"},{"id":"541ee70a-127b-4687-81a4-970f159afd01","title":"Tin","sourceUrl":"https://pubchem.ncbi.nlm.nih.gov/element/50","version":1,"createdAt":"2026-10-04T00:18:29.000Z","updatedAt":"2026-10-04T00:18:29.000Z","text":"Tin (Sn) is chemical element 50, a post-transition metal in group 14, period 5 (PubChem).\n\n- Atomic number: 50\n- Symbol: Sn\n- Group: 14\n- Period: 5\n- Atomic mass: 118.71 u\n- Electron configuration: [Kr]5s2 4d10 5p2\n- Electronegativity (Pauling scale): 1.96\n- Atomic radius (van der Waals): 217 pm\n- Ionization energy: 7.344 eV\n- Electron affinity: 1.2 eV\n- Oxidation states: +4, +2\n- Standard state: Solid\n- Melting point: 505.08 K\n- Boiling point: 2875 K\n- Density: 7.287 g/cm³\n- Chemical group: Post-transition metal\n- Year discovered: Ancient"}]}