{ "_meta": { "dataset": "4AB Periodic Table — 118 elements", "publisher": "4AB Great Service (ABC Chemistry)", "source_pages": "https://4ab.in/chemistry/periodic-table/", "built": "2026-10-01", "rows": 10, "sample": true, "licence": "Licence on request — write to Support@4ab.in", "note": "Values exactly as published on the 4AB periodic table pages (which cite IUPAC/CIAAW atomic weights, NIST ionization energies and CRC Handbook physical data). Empty = not given on the page. Some numeric columns hold text where the page prints text (e.g. predicted values).", "fields": [ { "column": "atomic_number", "meaning": "Atomic number (Z)", "unit": "" }, { "column": "symbol", "meaning": "Chemical symbol", "unit": "" }, { "column": "name", "meaning": "Element name", "unit": "" }, { "column": "slug", "meaning": "URL slug", "unit": "" }, { "column": "page_url", "meaning": "Element page on 4ab.in", "unit": "" }, { "column": "category", "meaning": "Category code", "unit": "" }, { "column": "category_label", "meaning": "Category", "unit": "" }, { "column": "group", "meaning": "Group (blank for f-block)", "unit": "" }, { "column": "period", "meaning": "Period", "unit": "" }, { "column": "block", "meaning": "Block", "unit": "" }, { "column": "table_column", "meaning": "Column in the 18-column table layout", "unit": "" }, { "column": "table_row", "meaning": "Row in the table layout (f-block rows separate)", "unit": "" }, { "column": "atomic_mass", "meaning": "Standard atomic weight", "unit": "u" }, { "column": "mass_is_mass_number", "meaning": "Mass is the mass number of the most stable isotope (no stable isotope)", "unit": "" }, { "column": "electron_configuration", "meaning": "Electron configuration", "unit": "" }, { "column": "electron_configuration_filling_order", "meaning": "Configuration (filling order)", "unit": "" }, { "column": "electrons_per_shell", "meaning": "Electrons per shell (K, L, M …)", "unit": "" }, { "column": "electronegativity_pauling", "meaning": "Electronegativity (Pauling)", "unit": "" }, { "column": "ionization_energy_1_ev", "meaning": "1st ionization energy", "unit": "eV" }, { "column": "ionization_energy_2_ev", "meaning": "2nd ionization energy", "unit": "eV" }, { "column": "ionization_energy_3_ev", "meaning": "3rd ionization energy", "unit": "eV" }, { "column": "ionization_energy_1_kj_mol", "meaning": "1st ionization energy", "unit": "kJ/mol" }, { "column": "ionization_energy_2_kj_mol", "meaning": "2nd ionization energy", "unit": "kJ/mol" }, { "column": "ionization_energy_3_kj_mol", "meaning": "3rd ionization energy", "unit": "kJ/mol" }, { "column": "electron_affinity_ev", "meaning": "Electron affinity", "unit": "eV" }, { "column": "electron_affinity_kj_mol", "meaning": "Electron affinity", "unit": "kJ/mol" }, { "column": "atomic_radius_empirical_pm", "meaning": "Atomic radius (empirical)", "unit": "pm" }, { "column": "atomic_radius_angstrom", "meaning": "Atomic radius", "unit": "Å" }, { "column": "covalent_radius_angstrom", "meaning": "Covalent radius", "unit": "Å" }, { "column": "ionic_radius_angstrom", "meaning": "Ionic radius", "unit": "Å" }, { "column": "radius_1plus_ion_pm", "meaning": "Radius of 1+ ion", "unit": "pm" }, { "column": "radius_2plus_ion_pm", "meaning": "Radius of 2+ ion", "unit": "pm" }, { "column": "radius_3plus_ion_pm", "meaning": "Radius of 3+ ion", "unit": "pm" }, { "column": "radius_1minus_ion_pm", "meaning": "Radius of 1− ion", "unit": "pm" }, { "column": "radius_2minus_ion_pm", "meaning": "Radius of 2− ion", "unit": "pm" }, { "column": "polarizability_a3", "meaning": "Polarizability", "unit": "ų" }, { "column": "atomic_volume_cm3_mol", "meaning": "Atomic volume", "unit": "cm³/mol" }, { "column": "density_g_cm3", "meaning": "Density", "unit": "g/cm³" }, { "column": "melting_point_c", "meaning": "Melting point", "unit": "°C" }, { "column": "boiling_point_c", "meaning": "Boiling point", "unit": "°C" }, { "column": "state_code", "meaning": "State code (s, l, g …)", "unit": "" }, { "column": "state", "meaning": "State at 25 °C", "unit": "" }, { "column": "crystal_structure", "meaning": "Crystal structure", "unit": "" }, { "column": "structure", "meaning": "Structure (description)", "unit": "" }, { "column": "color", "meaning": "Colour", "unit": "" }, { "column": "appearance", "meaning": "Appearance", "unit": "" }, { "column": "characteristics", "meaning": "Characteristics", "unit": "" }, { "column": "hardness_mohs", "meaning": "Hardness (Mohs)", "unit": "" }, { "column": "specific_heat_j_gk", "meaning": "Specific heat capacity", "unit": "J/(g·K)" }, { "column": "enthalpy_fusion_kj_mol", "meaning": "Enthalpy of fusion", "unit": "kJ/mol" }, { "column": "enthalpy_vaporization_kj_mol", "meaning": "Enthalpy of vaporization", "unit": "kJ/mol" }, { "column": "enthalpy_atomization_kj_mol", "meaning": "Enthalpy of atomization", "unit": "kJ/mol" }, { "column": "thermal_conductivity_w_mk", "meaning": "Thermal conductivity", "unit": "W/(m·K)" }, { "column": "electrical_conductivity", "meaning": "Electrical conductivity", "unit": "10⁶/(cm·Ω)" }, { "column": "oxidation_states", "meaning": "Oxidation states", "unit": "" }, { "column": "common_ions", "meaning": "Ions commonly formed", "unit": "" }, { "column": "reaction_air", "meaning": "Reaction with air", "unit": "" }, { "column": "reaction_water", "meaning": "Reaction with water", "unit": "" }, { "column": "reaction_hcl_6m", "meaning": "Reaction with 6 M HCl", "unit": "" }, { "column": "reaction_hno3_15m", "meaning": "Reaction with 15 M HNO₃", "unit": "" }, { "column": "reaction_naoh_6m", "meaning": "Reaction with 6 M NaOH", "unit": "" }, { "column": "hydride", "meaning": "Hydride(s)", "unit": "" }, { "column": "oxide", "meaning": "Oxide(s)", "unit": "" }, { "column": "chloride", "meaning": "Chloride(s)", "unit": "" }, { "column": "abundance_crust_mg_kg", "meaning": "Abundance, Earth's crust", "unit": "mg/kg" }, { "column": "abundance_seawater_mg_l", "meaning": "Abundance, seawater", "unit": "mg/L" }, { "column": "abundance_human_body_pct", "meaning": "Abundance, human body", "unit": "%" }, { "column": "abundance_crust_log", "meaning": "Abundance, Earth's crust (log scale)", "unit": "" }, { "column": "abundance_solar_log", "meaning": "Relative abundance, solar system (log scale, Si = 6)", "unit": "" }, { "column": "cost_pure_usd_per_100g", "meaning": "Cost, pure (number = US$ per 100 g; text as printed)", "unit": "US$/100 g" }, { "column": "cost_bulk_usd_per_100g", "meaning": "Cost, bulk (number = US$ per 100 g; text as printed)", "unit": "US$/100 g" }, { "column": "discovery_year", "meaning": "Discovery year", "unit": "" }, { "column": "discoverer", "meaning": "Discoverer", "unit": "" }, { "column": "naturally_occurring", "meaning": "Naturally occurring (false = synthetic)", "unit": "" }, { "column": "principal_source", "meaning": "Principal source", "unit": "" }, { "column": "name_de", "meaning": "Name in German", "unit": "" }, { "column": "name_fr", "meaning": "Name in French", "unit": "" }, { "column": "name_es", "meaning": "Name in Spanish", "unit": "" }, { "column": "name_it", "meaning": "Name in Italian", "unit": "" }, { "column": "cas_number", "meaning": "CAS Registry Number", "unit": "" }, { "column": "toxic", "meaning": "Toxic?", "unit": "" }, { "column": "carcinogenic", "meaning": "Carcinogenic?", "unit": "" }, { "column": "uses", "meaning": "Principal uses", "unit": "" }, { "column": "notes", "meaning": "Notes", "unit": "" }, { "column": "summary", "meaning": "One-line summary", "unit": "" } ] }, "elements": [ { "atomic_number": 1, "symbol": "H", "name": "Hydrogen", "slug": "hydrogen", "page_url": "https://4ab.in/chemistry/periodic-table/hydrogen/", "category": "nonmetal", "category_label": "Reactive nonmetal", "group": 1, "period": 1, "block": "s", "table_column": 1, "table_row": 1, "atomic_mass": 1.008, "mass_is_mass_number": false, "electron_configuration": "1s1", "electron_configuration_filling_order": "1s1", "electrons_per_shell": "1", "electronegativity_pauling": 2.2, "ionization_energy_1_ev": 13.5984, "ionization_energy_2_ev": null, "ionization_energy_3_ev": null, "ionization_energy_1_kj_mol": 1312.0, "ionization_energy_2_kj_mol": null, "ionization_energy_3_kj_mol": null, "electron_affinity_ev": 0.75, "electron_affinity_kj_mol": 72.0, "atomic_radius_empirical_pm": 37.1, "atomic_radius_angstrom": 0.79, "covalent_radius_angstrom": 0.32, "ionic_radius_angstrom": 1.54, "radius_1plus_ion_pm": null, "radius_2plus_ion_pm": null, "radius_3plus_ion_pm": null, "radius_1minus_ion_pm": null, "radius_2minus_ion_pm": null, "polarizability_a3": 0.7, "atomic_volume_cm3_mol": 14.4, "density_g_cm3": 6.99e-05, "melting_point_c": -259.1, "boiling_point_c": -252.9, "state_code": "g", "state": "Gas", "crystal_structure": "hexagonal", "structure": "hcp: hexagonal close pkd", "color": "colorless", "appearance": "colorless gas", "characteristics": "diatomic,densH2O", "reaction_water": "none", "reaction_hcl_6m": "none", "reaction_hno3_15m": "none", "reaction_naoh_6m": "none", "hydride": "H2", "oxide": "H2O", "chloride": "HCl", "abundance_crust_mg_kg": 1400.0, "abundance_seawater_mg_l": 108000.0, "abundance_human_body_pct": 10.0, "abundance_crust_log": 3.1, "abundance_solar_log": 10.4456042, "cost_pure_usd_per_100g": 12.0, "cost_bulk_usd_per_100g": "Not quoted (sold in small quantities)", "discovery_year": "1766", "discoverer": "Henry Cavendish", "naturally_occurring": true, "principal_source": "Water, methane", "name_de": "Wasserstoff", "name_fr": "hydrogène", "name_es": "hidrógeno", "name_it": "idrogeno", "cas_number": "1333-74-0", "toxic": "No (simple asphyxiant; flammable)", "carcinogenic": "No evidence", "uses": "rocket fuel", "notes": null, "summary": "Hydrogen is a chemical element with chemical symbol H and atomic number 1. With an atomic weight of 1.00794 u, hydrogen is the lightest element on the periodic table." }, { "atomic_number": 2, "symbol": "He", "name": "Helium", "slug": "helium", "page_url": "https://4ab.in/chemistry/periodic-table/helium/", "category": "noble", "category_label": "Noble gas", "group": 18, "period": 1, "block": "s", "table_column": 18, "table_row": 1, "atomic_mass": 4.0026, "mass_is_mass_number": false, "electron_configuration": "1s2", "electron_configuration_filling_order": "1s2", "electrons_per_shell": "2", "electronegativity_pauling": "None (no known compounds)", "ionization_energy_1_ev": 24.5874, "ionization_energy_2_ev": 54.416, "ionization_energy_3_ev": null, "ionization_energy_1_kj_mol": 2372.0, "ionization_energy_2_kj_mol": 5250.0, "ionization_energy_3_kj_mol": null, "electron_affinity_ev": "Not stable (anion unbound, < 0 eV)", "electron_affinity_kj_mol": "Not stable", "atomic_radius_empirical_pm": 31.0, "atomic_radius_angstrom": 0.49, "covalent_radius_angstrom": 0.93, "ionic_radius_angstrom": "Not measured", "radius_1plus_ion_pm": null, "radius_2plus_ion_pm": null, "radius_3plus_ion_pm": null, "radius_1minus_ion_pm": null, "radius_2minus_ion_pm": null, "polarizability_a3": 0.198, "atomic_volume_cm3_mol": 19.5, "density_g_cm3": 0.000179, "melting_point_c": -272.2, "boiling_point_c": -268.9, "state_code": "g", "state": "Gas", "crystal_structure": "hexagonal", "structure": "Not determined", "color": "colorless", "appearance": "colorless gas, exhibiting a red-orange glow when placed in a high-volt…", "characteristics": "Inert, densLi2O", "reaction_water": "mild, =>H2, LiOH", "reaction_hcl_6m": "vigorous, =>H2, LiCl", "reaction_hno3_15m": "vigorous, =>LiNO3", "reaction_naoh_6m": "mild, =>H2, LiOH", "hydride": "LiH", "oxide": "Li2O", "chloride": "LiCl", "abundance_crust_mg_kg": 20.0, "abundance_seawater_mg_l": 0.18, "abundance_human_body_pct": "Trace / not established", "abundance_crust_log": 1.3, "abundance_solar_log": 1.75663611, "cost_pure_usd_per_100g": 27.0, "cost_bulk_usd_per_100g": "Not quoted (sold in small quantities)", "discovery_year": "1817", "discoverer": "Johan August Arfwedson", "naturally_occurring": true, "principal_source": "Spodumene (silicate)", "name_de": "Lithium", "name_fr": "lithium", "name_es": "litio", "name_it": "litio", "cas_number": "7439-93-2", "toxic": "Moderate (salts)", "carcinogenic": "No evidence", "uses": "batteries, lubricant", "notes": null, "summary": "Lithium (from Greek:λίθος lithos, \"stone\") is a chemical element with the symbol Li and atomic number 3. It is a soft, silver-white metal belonging to the alkali metal group of chemical elements." }, { "atomic_number": 4, "symbol": "Be", "name": "Beryllium", "slug": "beryllium", "page_url": "https://4ab.in/chemistry/periodic-table/beryllium/", "category": "alkaline", "category_label": "Alkaline earth metal", "group": 2, "period": 2, "block": "s", "table_column": 2, "table_row": 2, "atomic_mass": 9.0122, "mass_is_mass_number": false, "electron_configuration": "[He] 2s2", "electron_configuration_filling_order": "[He] 2s2", "electrons_per_shell": "2, 2", "electronegativity_pauling": 1.57, "ionization_energy_1_ev": 9.3226, "ionization_energy_2_ev": 18.211, "ionization_energy_3_ev": 153.893, "ionization_energy_1_kj_mol": 899.0, "ionization_energy_2_kj_mol": 1757.0, "ionization_energy_3_kj_mol": 14848.0, "electron_affinity_ev": "Not stable (anion unbound, < 0 eV)", "electron_affinity_kj_mol": "Not stable", "atomic_radius_empirical_pm": 112.0, "atomic_radius_angstrom": 1.4, "covalent_radius_angstrom": 0.9, "ionic_radius_angstrom": 0.45, "radius_1plus_ion_pm": null, "radius_2plus_ion_pm": 59.0, "radius_3plus_ion_pm": null, "radius_1minus_ion_pm": null, "radius_2minus_ion_pm": null, "polarizability_a3": 5.6, "atomic_volume_cm3_mol": 5.0, "density_g_cm3": 1.85, "melting_point_c": 1278.0, "boiling_point_c": 2970.0, "state_code": "s", "state": "Solid", "crystal_structure": "hexagonal", "structure": "hcp: hexagonal close pkd", "color": "steel gray", "appearance": "white-gray metallic", "characteristics": "toxic", "hardness_mohs": 5.5, "specific_heat_j_gk": 1.82, "enthalpy_fusion_kj_mol": 12.2, "enthalpy_vaporization_kj_mol": 292.4, "enthalpy_atomization_kj_mol": 324.0, "thermal_conductivity_w_mk": 200.0, "electrical_conductivity": 0.313, "oxidation_states": "+2", "common_ions": "+2", "reaction_air": "vigorous, w/ht=>BeO,Be3N2", "reaction_water": "none", "reaction_hcl_6m": "mild, =>H2", "reaction_hno3_15m": "none", "reaction_naoh_6m": "mild, =>H2, [Be(OH)4](2-)", "hydride": "BeH2", "oxide": "BeO", "chloride": "BeCl2", "abundance_crust_mg_kg": 2.8, "abundance_seawater_mg_l": 5.6e-06, "abundance_human_body_pct": "Trace / not established", "abundance_crust_log": 0.4, "abundance_solar_log": -0.13667714, "cost_pure_usd_per_100g": 530.0, "cost_bulk_usd_per_100g": 59.0, "discovery_year": "1797", "discoverer": "Louis Nicolas Vauquelin", "naturally_occurring": true, "principal_source": "Beryl (silicate)", "name_de": "Beryllium", "name_fr": "béryllium", "name_es": "berilio", "name_it": "berillio", "cas_number": "7440-41-7", "toxic": "yes", "carcinogenic": "yes", "uses": "Cu alloys, X-ray windows", "notes": null, "summary": "Beryllium is a chemical element with symbol Be and atomic number 4. It is created through stellar nucleosynthesis and is a relatively rare element in the universe." }, { "atomic_number": 5, "symbol": "B", "name": "Boron", "slug": "boron", "page_url": "https://4ab.in/chemistry/periodic-table/boron/", "category": "metalloid", "category_label": "Metalloid", "group": 13, "period": 2, "block": "p", "table_column": 13, "table_row": 2, "atomic_mass": 10.81, "mass_is_mass_number": false, "electron_configuration": "[He] 2s2 2p1", "electron_configuration_filling_order": "[He] 2s2 2p1", "electrons_per_shell": "2, 3", "electronegativity_pauling": 2.04, "ionization_energy_1_ev": 8.298, "ionization_energy_2_ev": 25.154, "ionization_energy_3_ev": 37.93, "ionization_energy_1_kj_mol": 801.0, "ionization_energy_2_kj_mol": 2427.0, "ionization_energy_3_kj_mol": 3660.0, "electron_affinity_ev": 0.28, "electron_affinity_kj_mol": 27.0, "atomic_radius_empirical_pm": 85.0, "atomic_radius_angstrom": 1.17, "covalent_radius_angstrom": 0.82, "ionic_radius_angstrom": 0.23, "radius_1plus_ion_pm": null, "radius_2plus_ion_pm": null, "radius_3plus_ion_pm": 41.0, "radius_1minus_ion_pm": null, "radius_2minus_ion_pm": null, "polarizability_a3": 3.0, "atomic_volume_cm3_mol": 4.6, "density_g_cm3": 2.34, "melting_point_c": 2079.0, "boiling_point_c": 2550.0, "state_code": "s", "state": "Solid", "crystal_structure": "rhombohedral", "structure": "special: B12 icosahedra", "color": "black", "appearance": "black-brown", "characteristics": "B12 icosahedra; 3 forms", "hardness_mohs": 9.5, "specific_heat_j_gk": 1.02, "enthalpy_fusion_kj_mol": 50.2, "enthalpy_vaporization_kj_mol": 489.7, "enthalpy_atomization_kj_mol": 573.0, "thermal_conductivity_w_mk": 27.0, "electrical_conductivity": 0.0, "oxidation_states": "+3", "common_ions": "+3", "reaction_air": "mild, w/ht =>B2O3", "reaction_water": "none", "reaction_hcl_6m": "none", "reaction_hno3_15m": "none", "reaction_naoh_6m": "none", "hydride": "B2H6 and many BxHy", "oxide": "B2O3", "chloride": "BCl3 and many BxCly", "abundance_crust_mg_kg": 10.0, "abundance_seawater_mg_l": 4.44, "abundance_human_body_pct": 7e-05, "abundance_crust_log": 1.0, "abundance_solar_log": 1.32633586, "cost_pure_usd_per_100g": 250.0, "cost_bulk_usd_per_100g": "Not quoted (sold in small quantities)", "discovery_year": "1808", "discoverer": "Joseph Louis Gay-Lussac", "naturally_occurring": true, "principal_source": "Na and Ca borates (misc)", "name_de": "Bor", "name_fr": "bore", "name_es": "boro", "name_it": "boro", "cas_number": "7440-42-8", "toxic": "Low", "carcinogenic": "No evidence", "uses": "borax, glass making(B2O3)", "notes": "sublimes", "summary": "Boron is a metalloid chemical element with symbol B and atomic number 5. Produced entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, it is a low-abundance element in…" }, { "atomic_number": 6, "symbol": "C", "name": "Carbon", "slug": "carbon", "page_url": "https://4ab.in/chemistry/periodic-table/carbon/", "category": "nonmetal", "category_label": "Reactive nonmetal", "group": 14, "period": 2, "block": "p", "table_column": 14, "table_row": 2, "atomic_mass": 12.011, "mass_is_mass_number": false, "electron_configuration": "[He] 2s2 2p2", "electron_configuration_filling_order": "[He] 2s2 2p2", "electrons_per_shell": "2, 4", "electronegativity_pauling": 2.55, "ionization_energy_1_ev": 11.2603, "ionization_energy_2_ev": 24.383, "ionization_energy_3_ev": 47.887, "ionization_energy_1_kj_mol": 1086.0, "ionization_energy_2_kj_mol": 2353.0, "ionization_energy_3_kj_mol": 4620.0, "electron_affinity_ev": 1.26, "electron_affinity_kj_mol": 122.0, "atomic_radius_empirical_pm": 77.2, "atomic_radius_angstrom": 0.91, "covalent_radius_angstrom": 0.77, "ionic_radius_angstrom": 0.16, "radius_1plus_ion_pm": null, "radius_2plus_ion_pm": null, "radius_3plus_ion_pm": null, "radius_1minus_ion_pm": null, "radius_2minus_ion_pm": null, "polarizability_a3": 1.8, "atomic_volume_cm3_mol": 4.58, "density_g_cm3": 2.25, "melting_point_c": 3367.0, "boiling_point_c": 4827.0, "state_code": "s", "state": "Solid", "crystal_structure": "hexagonal", "structure": "hexagonal layers", "color": "black", "appearance": "black", "characteristics": "6 forms: graphite,diamond", "hardness_mohs": 0.8, "specific_heat_j_gk": 0.71, "enthalpy_fusion_kj_mol": "Sublimes (≈ 117 kJ/mol at triple point)", "enthalpy_vaporization_kj_mol": 355.8, "enthalpy_atomization_kj_mol": 717.0, "thermal_conductivity_w_mk": 129.0, "electrical_conductivity": 0.00061, "oxidation_states": "+4, +2, -4", "common_ions": "−4", "reaction_air": "vigorous, =>CO2", "reaction_water": "none", "reaction_hcl_6m": "none", "reaction_hno3_15m": "mild,w/ht=>C6(COOH)6", "reaction_naoh_6m": "none", "hydride": "CH4 and many CxHy", "oxide": "CO CO2", "chloride": "CCl4", "abundance_crust_mg_kg": 200.0, "abundance_seawater_mg_l": 28.0, "abundance_human_body_pct": 23.0, "abundance_crust_log": 2.3, "abundance_solar_log": 7.00432137, "cost_pure_usd_per_100g": 2.4, "cost_bulk_usd_per_100g": "Not quoted (sold in small quantities)", "discovery_year": "Ancient", "discoverer": "Ancient Egypt", "naturally_occurring": true, "principal_source": "Coal,Petroleum,Natural gas", "name_de": "Kohlenlstoff", "name_fr": "carbone", "name_es": "carbono", "name_it": "carbonio", "cas_number": "7440-44-0", "toxic": "No (as element)", "carcinogenic": "no", "uses": "fuel(coal), lubricant", "notes": "graphite", "summary": "Carbon (from Latin:carbo \"coal\") is a chemical element with symbol C and atomic number 6." }, { "atomic_number": 7, "symbol": "N", "name": "Nitrogen", "slug": "nitrogen", "page_url": "https://4ab.in/chemistry/periodic-table/nitrogen/", "category": "nonmetal", "category_label": "Reactive nonmetal", "group": 15, "period": 2, "block": "p", "table_column": 15, "table_row": 2, "atomic_mass": 14.007, "mass_is_mass_number": false, "electron_configuration": "[He] 2s2 2p3", "electron_configuration_filling_order": "[He] 2s2 2p3", "electrons_per_shell": "2, 5", "electronegativity_pauling": 3.04, "ionization_energy_1_ev": 14.5341, "ionization_energy_2_ev": 29.601, "ionization_energy_3_ev": 47.448, "ionization_energy_1_kj_mol": 1402.0, "ionization_energy_2_kj_mol": 2856.0, "ionization_energy_3_kj_mol": 4578.0, "electron_affinity_ev": "Not stable (anion unbound, < 0 eV)", "electron_affinity_kj_mol": "Not stable", "atomic_radius_empirical_pm": 70.0, "atomic_radius_angstrom": 0.75, "covalent_radius_angstrom": 0.75, "ionic_radius_angstrom": 1.71, "radius_1plus_ion_pm": null, "radius_2plus_ion_pm": null, "radius_3plus_ion_pm": 30.0, "radius_1minus_ion_pm": null, "radius_2minus_ion_pm": null, "polarizability_a3": 1.1, "atomic_volume_cm3_mol": 17.3, "density_g_cm3": 0.00125, "melting_point_c": -209.9, "boiling_point_c": -195.8, "state_code": "g", "state": "Gas", "crystal_structure": "hexagonal", "structure": "Molecular crystal when frozen", "color": "colorless", "appearance": "colorless gas, liquid or solid", "characteristics": "diatomic(N2)", "hardness_mohs": "Not applicable (gas)", "specific_heat_j_gk": 1.04, "enthalpy_fusion_kj_mol": 0.3604, "enthalpy_vaporization_kj_mol": 2.7928, "enthalpy_atomization_kj_mol": 473.0, "thermal_conductivity_w_mk": 0.02598, "electrical_conductivity": "Insulator (gas)", "oxidation_states": "-3, +3, +5", "common_ions": "−3", "reaction_air": "none", "reaction_water": "none", "reaction_hcl_6m": "none", "reaction_hno3_15m": "none", "reaction_naoh_6m": "none", "hydride": "NH3 N2H4 HN3", "oxide": "N2O NO NO2 N2O5", "chloride": "NCl3", "abundance_crust_mg_kg": 19.0, "abundance_seawater_mg_l": 50.0, "abundance_human_body_pct": 2.6, "abundance_crust_log": 1.3, "abundance_solar_log": 6.49554434, "cost_pure_usd_per_100g": 0.4, "cost_bulk_usd_per_100g": "Not quoted (sold in small quantities)", "discovery_year": "1772", "discoverer": "Daniel Rutherford", "naturally_occurring": true, "principal_source": "Air", "name_de": "Stickstoff", "name_fr": "azote", "name_es": "nitrógeno", "name_it": "azoto", "cas_number": "77727-37-9", "toxic": "no", "carcinogenic": "no", "uses": "fertilizer, cryogenics", "notes": null, "summary": "Nitrogen is a chemical element with symbol N and atomic number 7. It is the lightest pnictogen and at room temperature, it is a transparent, odorless diatomic gas." }, { "atomic_number": 8, "symbol": "O", "name": "Oxygen", "slug": "oxygen", "page_url": "https://4ab.in/chemistry/periodic-table/oxygen/", "category": "nonmetal", "category_label": "Reactive nonmetal", "group": 16, "period": 2, "block": "p", "table_column": 16, "table_row": 2, "atomic_mass": 15.999, "mass_is_mass_number": false, "electron_configuration": "[He] 2s2 2p4", "electron_configuration_filling_order": "[He] 2s2 2p4", "electrons_per_shell": "2, 6", "electronegativity_pauling": 3.44, "ionization_energy_1_ev": 13.6181, "ionization_energy_2_ev": 35.117, "ionization_energy_3_ev": 54.934, "ionization_energy_1_kj_mol": 1314.0, "ionization_energy_2_kj_mol": 3388.0, "ionization_energy_3_kj_mol": 5300.0, "electron_affinity_ev": 1.46, "electron_affinity_kj_mol": 141.0, "atomic_radius_empirical_pm": 73.0, "atomic_radius_angstrom": 0.65, "covalent_radius_angstrom": 0.73, "ionic_radius_angstrom": 1.4, "radius_1plus_ion_pm": null, "radius_2plus_ion_pm": null, "radius_3plus_ion_pm": null, "radius_1minus_ion_pm": null, "radius_2minus_ion_pm": 126.0, "polarizability_a3": 0.793, "atomic_volume_cm3_mol": 14.0, "density_g_cm3": 0.00143, "melting_point_c": -218.4, "boiling_point_c": -183.0, "state_code": "g", "state": "Gas", "crystal_structure": "cubic", "structure": "Molecular crystal when frozen", "color": "colorless", "appearance": "colorless", "characteristics": "diatomic,2 forms: O2, O3", "hardness_mohs": "Not applicable (gas)", "specific_heat_j_gk": 0.92, "enthalpy_fusion_kj_mol": 0.22259, "enthalpy_vaporization_kj_mol": 3.4099, "enthalpy_atomization_kj_mol": 249.0, "thermal_conductivity_w_mk": 0.02674, "electrical_conductivity": "Insulator (gas)", "oxidation_states": "-2", "common_ions": "−2", "reaction_air": "none", "reaction_water": "none", "reaction_hcl_6m": "none", "reaction_hno3_15m": "none", "reaction_naoh_6m": "none", "hydride": "H2O", "oxide": "O2 O3", "chloride": "Cl2O ClO2 Cl2O7", "abundance_crust_mg_kg": 461000.0, "abundance_seawater_mg_l": 857000.0, "abundance_human_body_pct": 61.0, "abundance_crust_log": 5.7, "abundance_solar_log": 7.37657696, "cost_pure_usd_per_100g": 0.3, "cost_bulk_usd_per_100g": "Not quoted (sold in small quantities)", "discovery_year": "1774", "discoverer": "Carl Wilhelm Scheele", "naturally_occurring": true, "principal_source": "Air", "name_de": "Sauerstoff", "name_fr": "oxygène", "name_es": "oxígeno", "name_it": "ossigeno", "cas_number": "7782-44-7", "toxic": "no", "carcinogenic": "no", "uses": "rocket fuel, steel mfr.", "notes": null, "summary": "Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table and is a highly reactive nonmetal and oxidizing agent that readily forms com…" }, { "atomic_number": 9, "symbol": "F", "name": "Fluorine", "slug": "fluorine", "page_url": "https://4ab.in/chemistry/periodic-table/fluorine/", "category": "halogen", "category_label": "Halogen", "group": 17, "period": 2, "block": "p", "table_column": 17, "table_row": 2, "atomic_mass": 18.998, "mass_is_mass_number": false, "electron_configuration": "[He] 2s2 2p5", "electron_configuration_filling_order": "[He] 2s2 2p5", "electrons_per_shell": "2, 7", "electronegativity_pauling": 3.98, "ionization_energy_1_ev": 17.4228, "ionization_energy_2_ev": 34.97, "ionization_energy_3_ev": 62.707, "ionization_energy_1_kj_mol": 1681.0, "ionization_energy_2_kj_mol": 3374.0, "ionization_energy_3_kj_mol": 6050.0, "electron_affinity_ev": 3.4, "electron_affinity_kj_mol": 328.0, "atomic_radius_empirical_pm": 72.0, "atomic_radius_angstrom": 0.57, "covalent_radius_angstrom": 0.72, "ionic_radius_angstrom": 1.33, "radius_1plus_ion_pm": null, "radius_2plus_ion_pm": null, "radius_3plus_ion_pm": null, "radius_1minus_ion_pm": 119.0, "radius_2minus_ion_pm": null, "polarizability_a3": 0.634, "atomic_volume_cm3_mol": 12.6, "density_g_cm3": 0.0017, "melting_point_c": -219.8, "boiling_point_c": -188.1, "state_code": "g", "state": "Gas", "crystal_structure": "cubic", "structure": "layers of F2", "color": "colorless", "appearance": "colorless", "characteristics": "diatomic(F2), corrosive", "hardness_mohs": "Not applicable (gas)", "specific_heat_j_gk": 0.82, "enthalpy_fusion_kj_mol": 0.2552, "enthalpy_vaporization_kj_mol": 3.2698, "enthalpy_atomization_kj_mol": 79.0, "thermal_conductivity_w_mk": 0.0279, "electrical_conductivity": "Insulator (gas)", "oxidation_states": "-1", "common_ions": "−1", "reaction_air": "none", "reaction_water": "vigorous, =>HF, OF2", "reaction_hcl_6m": "vigorous, =>HF, OF2, ClF3", "reaction_hno3_15m": "Not reported", "reaction_naoh_6m": "vigorous, =>O2, NaF", "hydride": "HF", "oxide": "OF2", "chloride": "ClF ClF3 ClF5", "abundance_crust_mg_kg": 585.0, "abundance_seawater_mg_l": 1.3, "abundance_human_body_pct": 0.0033, "abundance_crust_log": 2.8, "abundance_solar_log": 2.92582757, "cost_pure_usd_per_100g": 190.0, "cost_bulk_usd_per_100g": "Not quoted (sold in small quantities)", "discovery_year": "1886", "discoverer": "André-Marie Ampère", "naturally_occurring": true, "principal_source": "Fluorite (misc)", "name_de": "Fluor", "name_fr": "fluor", "name_es": "flúor", "name_it": "fluoro", "cas_number": "7782-41-4", "toxic": "yes", "carcinogenic": "no", "uses": "fluorocarbons, toothpaste", "notes": null, "summary": "Fluorine is a chemical element with symbol F and atomic number 9. It is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions." }, { "atomic_number": 10, "symbol": "Ne", "name": "Neon", "slug": "neon", "page_url": "https://4ab.in/chemistry/periodic-table/neon/", "category": "noble", "category_label": "Noble gas", "group": 18, "period": 2, "block": "p", "table_column": 18, "table_row": 2, "atomic_mass": 20.18, "mass_is_mass_number": false, "electron_configuration": "[He] 2s2 2p6", "electron_configuration_filling_order": "[He] 2s2 2p6", "electrons_per_shell": "2, 8", "electronegativity_pauling": "None (no known compounds)", "ionization_energy_1_ev": 21.5645, "ionization_energy_2_ev": 40.962, "ionization_energy_3_ev": 63.45, "ionization_energy_1_kj_mol": 2081.0, "ionization_energy_2_kj_mol": 3952.0, "ionization_energy_3_kj_mol": 6122.0, "electron_affinity_ev": "Not stable (anion unbound, < 0 eV)", "electron_affinity_kj_mol": "Not stable", "atomic_radius_empirical_pm": 71.0, "atomic_radius_angstrom": 0.51, "covalent_radius_angstrom": 0.71, "ionic_radius_angstrom": "Not measured", "radius_1plus_ion_pm": null, "radius_2plus_ion_pm": null, "radius_3plus_ion_pm": null, "radius_1minus_ion_pm": null, "radius_2minus_ion_pm": null, "polarizability_a3": 0.396, "atomic_volume_cm3_mol": 17.3, "density_g_cm3": 0.0009, "melting_point_c": -248.0, "boiling_point_c": -248.7, "state_code": "g", "state": "Gas", "crystal_structure": "cubic: face centered", "structure": "fcc: face-centered cubic", "color": "colorless", "appearance": "colorless gas exhibiting an orange-red glow when placed in a high volt…", "characteristics": "Inert, dens