# Periodic Table of Elements

> The free, citation-ready periodic table of elements — 118 guides, trends, calculators, and printable PDFs.

A multilingual interactive periodic table of the chemical elements with element detail pages, periodic trends, printable PDFs, isotope data, and cited scientific references.

## Elements

- [Elements](https://periodic-table-of-elements.top/id/): Interactive periodic table with 8 property heatmaps, search, and learning entry points.
- [Semua unsur](https://periodic-table-of-elements.top/id/elements): Browse, filter, and search all 118 elements with detailed data.
- [Tren periodik](https://periodic-table-of-elements.top/id/trends): How electronegativity, atomic radius, ionization energy, melting point, density, boiling point, atomic mass, and electron affinity vary across periods and down groups.
- [Tools](https://periodic-table-of-elements.top/id/tools): Molar mass calculator, equation balancer, electron configuration tool, and element comparator.
- [Learn](https://periodic-table-of-elements.top/id/learn): Articles explaining periodic table concepts, electron configuration, atomic mass, history, and how to memorize element symbols.
- [Tabel periodik cetakan](https://periodic-table-of-elements.top/id/printables): Download high-resolution PDFs and PNGs of the periodic table for study and classroom use.
- [Sumber data](https://periodic-table-of-elements.top/id/data-sources): Authoritative references: IUPAC/CIAAW, PubChem, NIST, Bowserinator/Periodic-Table-JSON. Field-level units, ranges, and conflict resolution rules.

## Semua unsur (118 total)

- [Hydrogen (H, 1)](https://periodic-table-of-elements.top/id/elements/hydrogen): H, atomic number 1, atomic mass 1.008 u, reactive nonmetal.
- [Helium (He, 2)](https://periodic-table-of-elements.top/id/elements/helium): He, atomic number 2, atomic mass 4.002602 u, noble gas.
- [Lithium (Li, 3)](https://periodic-table-of-elements.top/id/elements/lithium): Li, atomic number 3, atomic mass 6.94 u, alkali metal.
- [Beryllium (Be, 4)](https://periodic-table-of-elements.top/id/elements/beryllium): Be, atomic number 4, atomic mass 9.0121831 u, alkaline earth metal.
- [Boron (B, 5)](https://periodic-table-of-elements.top/id/elements/boron): B, atomic number 5, atomic mass 10.81 u, metalloid.
- [Carbon (C, 6)](https://periodic-table-of-elements.top/id/elements/carbon): C, atomic number 6, atomic mass 12.011 u, reactive nonmetal.
- [Nitrogen (N, 7)](https://periodic-table-of-elements.top/id/elements/nitrogen): N, atomic number 7, atomic mass 14.007 u, reactive nonmetal.
- [Oxygen (O, 8)](https://periodic-table-of-elements.top/id/elements/oxygen): O, atomic number 8, atomic mass 15.999 u, reactive nonmetal.
- [Fluorine (F, 9)](https://periodic-table-of-elements.top/id/elements/fluorine): F, atomic number 9, atomic mass 18.998403162 u, reactive nonmetal.
- [Neon (Ne, 10)](https://periodic-table-of-elements.top/id/elements/neon): Ne, atomic number 10, atomic mass 20.1797 u, noble gas.
- [Sodium (Na, 11)](https://periodic-table-of-elements.top/id/elements/sodium): Na, atomic number 11, atomic mass 22.98976928 u, alkali metal.
- [Magnesium (Mg, 12)](https://periodic-table-of-elements.top/id/elements/magnesium): Mg, atomic number 12, atomic mass 24.305 u, alkaline earth metal.
- [Aluminum (Al, 13)](https://periodic-table-of-elements.top/id/elements/aluminum): Al, atomic number 13, atomic mass 26.9815384 u, post-transition metal.
- [Silicon (Si, 14)](https://periodic-table-of-elements.top/id/elements/silicon): Si, atomic number 14, atomic mass 28.085 u, metalloid.
- [Phosphorus (P, 15)](https://periodic-table-of-elements.top/id/elements/phosphorus): P, atomic number 15, atomic mass 30.973761998 u, reactive nonmetal.
- [Sulfur (S, 16)](https://periodic-table-of-elements.top/id/elements/sulfur): S, atomic number 16, atomic mass 32.06 u, reactive nonmetal.
- [Chlorine (Cl, 17)](https://periodic-table-of-elements.top/id/elements/chlorine): Cl, atomic number 17, atomic mass 35.45 u, reactive nonmetal.
- [Argon (Ar, 18)](https://periodic-table-of-elements.top/id/elements/argon): Ar, atomic number 18, atomic mass 39.948 u, noble gas.
- [Potassium (K, 19)](https://periodic-table-of-elements.top/id/elements/potassium): K, atomic number 19, atomic mass 39.0983 u, alkali metal.
- [Calcium (Ca, 20)](https://periodic-table-of-elements.top/id/elements/calcium): Ca, atomic number 20, atomic mass 40.078 u, alkaline earth metal.
- [Scandium (Sc, 21)](https://periodic-table-of-elements.top/id/elements/scandium): Sc, atomic number 21, atomic mass 44.955907 u, transition metal.
- [Titanium (Ti, 22)](https://periodic-table-of-elements.top/id/elements/titanium): Ti, atomic number 22, atomic mass 47.867 u, transition metal.
- [Vanadium (V, 23)](https://periodic-table-of-elements.top/id/elements/vanadium): V, atomic number 23, atomic mass 50.9415 u, transition metal.
- [Chromium (Cr, 24)](https://periodic-table-of-elements.top/id/elements/chromium): Cr, atomic number 24, atomic mass 51.9961 u, transition metal.
- [Manganese (Mn, 25)](https://periodic-table-of-elements.top/id/elements/manganese): Mn, atomic number 25, atomic mass 54.938043 u, transition metal.
- [Iron (Fe, 26)](https://periodic-table-of-elements.top/id/elements/iron): Fe, atomic number 26, atomic mass 55.845 u, transition metal.
- [Cobalt (Co, 27)](https://periodic-table-of-elements.top/id/elements/cobalt): Co, atomic number 27, atomic mass 58.933194 u, transition metal.
- [Nickel (Ni, 28)](https://periodic-table-of-elements.top/id/elements/nickel): Ni, atomic number 28, atomic mass 58.6934 u, transition metal.
- [Copper (Cu, 29)](https://periodic-table-of-elements.top/id/elements/copper): Cu, atomic number 29, atomic mass 63.546 u, transition metal.
- [Zinc (Zn, 30)](https://periodic-table-of-elements.top/id/elements/zinc): Zn, atomic number 30, atomic mass 65.38 u, transition metal.
- [Gallium (Ga, 31)](https://periodic-table-of-elements.top/id/elements/gallium): Ga, atomic number 31, atomic mass 69.723 u, post-transition metal.
- [Germanium (Ge, 32)](https://periodic-table-of-elements.top/id/elements/germanium): Ge, atomic number 32, atomic mass 72.63 u, metalloid.
- [Arsenic (As, 33)](https://periodic-table-of-elements.top/id/elements/arsenic): As, atomic number 33, atomic mass 74.921595 u, metalloid.
- [Selenium (Se, 34)](https://periodic-table-of-elements.top/id/elements/selenium): Se, atomic number 34, atomic mass 78.971 u, reactive nonmetal.
- [Bromine (Br, 35)](https://periodic-table-of-elements.top/id/elements/bromine): Br, atomic number 35, atomic mass 79.904 u, reactive nonmetal.
- [Krypton (Kr, 36)](https://periodic-table-of-elements.top/id/elements/krypton): Kr, atomic number 36, atomic mass 83.798 u, noble gas.
- [Rubidium (Rb, 37)](https://periodic-table-of-elements.top/id/elements/rubidium): Rb, atomic number 37, atomic mass 85.4678 u, alkali metal.
- [Strontium (Sr, 38)](https://periodic-table-of-elements.top/id/elements/strontium): Sr, atomic number 38, atomic mass 87.62 u, alkaline earth metal.
- [Yttrium (Y, 39)](https://periodic-table-of-elements.top/id/elements/yttrium): Y, atomic number 39, atomic mass 88.905838 u, transition metal.
- [Zirconium (Zr, 40)](https://periodic-table-of-elements.top/id/elements/zirconium): Zr, atomic number 40, atomic mass 91.224 u, transition metal.
- [Niobium (Nb, 41)](https://periodic-table-of-elements.top/id/elements/niobium): Nb, atomic number 41, atomic mass 92.90637 u, transition metal.
- [Molybdenum (Mo, 42)](https://periodic-table-of-elements.top/id/elements/molybdenum): Mo, atomic number 42, atomic mass 95.95 u, transition metal.
- [Technetium (Tc, 43)](https://periodic-table-of-elements.top/id/elements/technetium): Tc, atomic number 43, atomic mass 98 u, transition metal.
- [Ruthenium (Ru, 44)](https://periodic-table-of-elements.top/id/elements/ruthenium): Ru, atomic number 44, atomic mass 101.07 u, transition metal.
- [Rhodium (Rh, 45)](https://periodic-table-of-elements.top/id/elements/rhodium): Rh, atomic number 45, atomic mass 102.90549 u, transition metal.
- [Palladium (Pd, 46)](https://periodic-table-of-elements.top/id/elements/palladium): Pd, atomic number 46, atomic mass 106.42 u, transition metal.
- [Silver (Ag, 47)](https://periodic-table-of-elements.top/id/elements/silver): Ag, atomic number 47, atomic mass 107.8682 u, transition metal.
- [Cadmium (Cd, 48)](https://periodic-table-of-elements.top/id/elements/cadmium): Cd, atomic number 48, atomic mass 112.414 u, transition metal.
- [Indium (In, 49)](https://periodic-table-of-elements.top/id/elements/indium): In, atomic number 49, atomic mass 114.818 u, post-transition metal.
- [Tin (Sn, 50)](https://periodic-table-of-elements.top/id/elements/tin): Sn, atomic number 50, atomic mass 118.710 u, post-transition metal.
- [Antimony (Sb, 51)](https://periodic-table-of-elements.top/id/elements/antimony): Sb, atomic number 51, atomic mass 121.760 u, metalloid.
- [Tellurium (Te, 52)](https://periodic-table-of-elements.top/id/elements/tellurium): Te, atomic number 52, atomic mass 127.60 u, metalloid.
- [Iodine (I, 53)](https://periodic-table-of-elements.top/id/elements/iodine): I, atomic number 53, atomic mass 126.90447 u, reactive nonmetal.
- [Xenon (Xe, 54)](https://periodic-table-of-elements.top/id/elements/xenon): Xe, atomic number 54, atomic mass 131.293 u, noble gas.
- [Cesium (Cs, 55)](https://periodic-table-of-elements.top/id/elements/cesium): Cs, atomic number 55, atomic mass 132.90545196 u, alkali metal.
- [Barium (Ba, 56)](https://periodic-table-of-elements.top/id/elements/barium): Ba, atomic number 56, atomic mass 137.327 u, alkaline earth metal.
- [Lanthanum (La, 57)](https://periodic-table-of-elements.top/id/elements/lanthanum): La, atomic number 57, atomic mass 138.90547 u, lanthanide.
- [Cerium (Ce, 58)](https://periodic-table-of-elements.top/id/elements/cerium): Ce, atomic number 58, atomic mass 140.116 u, lanthanide.
- [Praseodymium (Pr, 59)](https://periodic-table-of-elements.top/id/elements/praseodymium): Pr, atomic number 59, atomic mass 140.90766 u, lanthanide.
- [Neodymium (Nd, 60)](https://periodic-table-of-elements.top/id/elements/neodymium): Nd, atomic number 60, atomic mass 144.242 u, lanthanide.
- [Promethium (Pm, 61)](https://periodic-table-of-elements.top/id/elements/promethium): Pm, atomic number 61, atomic mass 145 u, lanthanide.
- [Samarium (Sm, 62)](https://periodic-table-of-elements.top/id/elements/samarium): Sm, atomic number 62, atomic mass 150.36 u, lanthanide.
- [Europium (Eu, 63)](https://periodic-table-of-elements.top/id/elements/europium): Eu, atomic number 63, atomic mass 151.964 u, lanthanide.
- [Gadolinium (Gd, 64)](https://periodic-table-of-elements.top/id/elements/gadolinium): Gd, atomic number 64, atomic mass 157.25 u, lanthanide.
- [Terbium (Tb, 65)](https://periodic-table-of-elements.top/id/elements/terbium): Tb, atomic number 65, atomic mass 158.925354 u, lanthanide.
- [Dysprosium (Dy, 66)](https://periodic-table-of-elements.top/id/elements/dysprosium): Dy, atomic number 66, atomic mass 162.500 u, lanthanide.
- [Holmium (Ho, 67)](https://periodic-table-of-elements.top/id/elements/holmium): Ho, atomic number 67, atomic mass 164.930329 u, lanthanide.
- [Erbium (Er, 68)](https://periodic-table-of-elements.top/id/elements/erbium): Er, atomic number 68, atomic mass 167.259 u, lanthanide.
- [Thulium (Tm, 69)](https://periodic-table-of-elements.top/id/elements/thulium): Tm, atomic number 69, atomic mass 168.934219 u, lanthanide.
- [Ytterbium (Yb, 70)](https://periodic-table-of-elements.top/id/elements/ytterbium): Yb, atomic number 70, atomic mass 173.045 u, lanthanide.
- [Lutetium (Lu, 71)](https://periodic-table-of-elements.top/id/elements/lutetium): Lu, atomic number 71, atomic mass 174.9668 u, lanthanide.
- [Hafnium (Hf, 72)](https://periodic-table-of-elements.top/id/elements/hafnium): Hf, atomic number 72, atomic mass 178.486 u, transition metal.
- [Tantalum (Ta, 73)](https://periodic-table-of-elements.top/id/elements/tantalum): Ta, atomic number 73, atomic mass 180.94788 u, transition metal.
- [Tungsten (W, 74)](https://periodic-table-of-elements.top/id/elements/tungsten): W, atomic number 74, atomic mass 183.84 u, transition metal.
- [Rhenium (Re, 75)](https://periodic-table-of-elements.top/id/elements/rhenium): Re, atomic number 75, atomic mass 186.207 u, transition metal.
- [Osmium (Os, 76)](https://periodic-table-of-elements.top/id/elements/osmium): Os, atomic number 76, atomic mass 190.23 u, transition metal.
- [Iridium (Ir, 77)](https://periodic-table-of-elements.top/id/elements/iridium): Ir, atomic number 77, atomic mass 192.217 u, transition metal.
- [Platinum (Pt, 78)](https://periodic-table-of-elements.top/id/elements/platinum): Pt, atomic number 78, atomic mass 195.084 u, transition metal.
- [Gold (Au, 79)](https://periodic-table-of-elements.top/id/elements/gold): Au, atomic number 79, atomic mass 196.966570 u, transition metal.
- [Mercury (Hg, 80)](https://periodic-table-of-elements.top/id/elements/mercury): Hg, atomic number 80, atomic mass 200.59 u, transition metal.
- [Thallium (Tl, 81)](https://periodic-table-of-elements.top/id/elements/thallium): Tl, atomic number 81, atomic mass 204.38 u, post-transition metal.
- [Lead (Pb, 82)](https://periodic-table-of-elements.top/id/elements/lead): Pb, atomic number 82, atomic mass 207.2 u, post-transition metal.
- [Bismuth (Bi, 83)](https://periodic-table-of-elements.top/id/elements/bismuth): Bi, atomic number 83, atomic mass 208.98040 u, post-transition metal.
- [Polonium (Po, 84)](https://periodic-table-of-elements.top/id/elements/polonium): Po, atomic number 84, atomic mass 209 u, post-transition metal.
- [Astatine (At, 85)](https://periodic-table-of-elements.top/id/elements/astatine): At, atomic number 85, atomic mass 210 u, metalloid.
- [Radon (Rn, 86)](https://periodic-table-of-elements.top/id/elements/radon): Rn, atomic number 86, atomic mass 222 u, noble gas.
- [Francium (Fr, 87)](https://periodic-table-of-elements.top/id/elements/francium): Fr, atomic number 87, atomic mass 223 u, alkali metal.
- [Radium (Ra, 88)](https://periodic-table-of-elements.top/id/elements/radium): Ra, atomic number 88, atomic mass 226 u, alkaline earth metal.
- [Actinium (Ac, 89)](https://periodic-table-of-elements.top/id/elements/actinium): Ac, atomic number 89, atomic mass 227 u, actinide.
- [Thorium (Th, 90)](https://periodic-table-of-elements.top/id/elements/thorium): Th, atomic number 90, atomic mass 232.0377 u, actinide.
- [Protactinium (Pa, 91)](https://periodic-table-of-elements.top/id/elements/protactinium): Pa, atomic number 91, atomic mass 231.03588 u, actinide.
- [Uranium (U, 92)](https://periodic-table-of-elements.top/id/elements/uranium): U, atomic number 92, atomic mass 238.02891 u, actinide.
- [Neptunium (Np, 93)](https://periodic-table-of-elements.top/id/elements/neptunium): Np, atomic number 93, atomic mass 237 u, actinide.
- [Plutonium (Pu, 94)](https://periodic-table-of-elements.top/id/elements/plutonium): Pu, atomic number 94, atomic mass 244 u, actinide.
- [Americium (Am, 95)](https://periodic-table-of-elements.top/id/elements/americium): Am, atomic number 95, atomic mass 243 u, actinide.
- [Curium (Cm, 96)](https://periodic-table-of-elements.top/id/elements/curium): Cm, atomic number 96, atomic mass 247 u, actinide.
- [Berkelium (Bk, 97)](https://periodic-table-of-elements.top/id/elements/berkelium): Bk, atomic number 97, atomic mass 247 u, actinide.
- [Californium (Cf, 98)](https://periodic-table-of-elements.top/id/elements/californium): Cf, atomic number 98, atomic mass 251 u, actinide.
- [Einsteinium (Es, 99)](https://periodic-table-of-elements.top/id/elements/einsteinium): Es, atomic number 99, atomic mass 252 u, actinide.
- [Fermium (Fm, 100)](https://periodic-table-of-elements.top/id/elements/fermium): Fm, atomic number 100, atomic mass 257 u, actinide.
- [Mendelevium (Md, 101)](https://periodic-table-of-elements.top/id/elements/mendelevium): Md, atomic number 101, atomic mass 258 u, actinide.
- [Nobelium (No, 102)](https://periodic-table-of-elements.top/id/elements/nobelium): No, atomic number 102, atomic mass 259 u, actinide.
- [Lawrencium (Lr, 103)](https://periodic-table-of-elements.top/id/elements/lawrencium): Lr, atomic number 103, atomic mass 266 u, actinide.
- [Rutherfordium (Rf, 104)](https://periodic-table-of-elements.top/id/elements/rutherfordium): Rf, atomic number 104, atomic mass 267 u, transition metal.
- [Dubnium (Db, 105)](https://periodic-table-of-elements.top/id/elements/dubnium): Db, atomic number 105, atomic mass 268 u, transition metal.
- [Seaborgium (Sg, 106)](https://periodic-table-of-elements.top/id/elements/seaborgium): Sg, atomic number 106, atomic mass 269 u, transition metal.
- [Bohrium (Bh, 107)](https://periodic-table-of-elements.top/id/elements/bohrium): Bh, atomic number 107, atomic mass 270 u, transition metal.
- [Hassium (Hs, 108)](https://periodic-table-of-elements.top/id/elements/hassium): Hs, atomic number 108, atomic mass 270 u, transition metal.
- [Meitnerium (Mt, 109)](https://periodic-table-of-elements.top/id/elements/meitnerium): Mt, atomic number 109, atomic mass 278 u, unknown.
- [Darmstadtium (Ds, 110)](https://periodic-table-of-elements.top/id/elements/darmstadtium): Ds, atomic number 110, atomic mass 281 u, unknown.
- [Roentgenium (Rg, 111)](https://periodic-table-of-elements.top/id/elements/roentgenium): Rg, atomic number 111, atomic mass 282 u, unknown.
- [Copernicium (Cn, 112)](https://periodic-table-of-elements.top/id/elements/copernicium): Cn, atomic number 112, atomic mass 285 u, unknown.
- [Nihonium (Nh, 113)](https://periodic-table-of-elements.top/id/elements/nihonium): Nh, atomic number 113, atomic mass 286 u, unknown.
- [Flerovium (Fl, 114)](https://periodic-table-of-elements.top/id/elements/flerovium): Fl, atomic number 114, atomic mass 289 u, unknown.
- [Moscovium (Mc, 115)](https://periodic-table-of-elements.top/id/elements/moscovium): Mc, atomic number 115, atomic mass 290 u, unknown.
- [Livermorium (Lv, 116)](https://periodic-table-of-elements.top/id/elements/livermorium): Lv, atomic number 116, atomic mass 293 u, unknown.
- [Tennessine (Ts, 117)](https://periodic-table-of-elements.top/id/elements/tennessine): Ts, atomic number 117, atomic mass 294 u, unknown.
- [Oganesson (Og, 118)](https://periodic-table-of-elements.top/id/elements/oganesson): Og, atomic number 118, atomic mass 294 u, unknown.

## Tren periodik

- [Electronegativity](https://periodic-table-of-elements.top/id/trends/electronegativity): A measure of the tendency of an atom to attract a bonding pair of electrons. (unit: Pauling).
- [Atomic Radius](https://periodic-table-of-elements.top/id/trends/atomic_radius): The distance from the center of the nucleus to the boundary of the surrounding cloud of electrons. (unit: pm).
- [Ionization Energy](https://periodic-table-of-elements.top/id/trends/ionization_energy): The energy required to remove the most loosely bound electron from a neutral gaseous atom. (unit: kJ/mol).
- [Melting Point](https://periodic-table-of-elements.top/id/trends/melting_point): The temperature at which the solid phase of a pure substance is in equilibrium with its liquid phase at atmospheric pressure. (unit: K).
- [Density at STP](https://periodic-table-of-elements.top/id/trends/density_stp): Mass per unit volume of a substance at standard temperature and pressure. (unit: g/cm3).
- [Boiling Point](https://periodic-table-of-elements.top/id/trends/boiling_point): The temperature at which the vapor pressure of a liquid equals the external atmospheric pressure. (unit: K).
- [Atomic Mass](https://periodic-table-of-elements.top/id/trends/atomic_mass): The mass of an atom, typically expressed in unified atomic mass units. (unit: u).
- [Electron Affinity](https://periodic-table-of-elements.top/id/trends/electron_affinity): The amount of energy released when an electron is added to a neutral atom in the gaseous state. (unit: kJ/mol).
- [Thermal Conductivity](https://periodic-table-of-elements.top/id/trends/thermal_conductivity): Rate at which heat flows through a material. Metals conduct heat well; gases and nonmetals poorly. (unit: W/(m·K)).
- [Crustal Abundance](https://periodic-table-of-elements.top/id/trends/abundance_crust): How much of the element is found in the Earth's crust, measured in milligrams per kilogram of crustal rock. (unit: mg/kg).
- [Oxidation States](https://periodic-table-of-elements.top/id/trends/oxidation_states): Number of distinct oxidation states the element commonly exhibits in compounds. (unit: count).

## Tabel periodik cetakan

- [Periodic Table (Color)](https://periodic-table-of-elements.top/id/printables#periodic-table-color): Full-color A4 / Letter PDF, all 118 elements with categories.
- [Periodic Table (Wide)](https://periodic-table-of-elements.top/id/printables#periodic-table-wide): Wide-format PDF for landscape printing across two pages.
- [Elements Poster 1](https://periodic-table-of-elements.top/id/printables#pdf-1): High-resolution PNG poster of element symbols and atomic numbers.
- [Elements Poster 2](https://periodic-table-of-elements.top/id/printables#pdf-2): High-resolution PNG poster with category colors.
- [Elements Poster 3](https://periodic-table-of-elements.top/id/printables#pdf-3): High-resolution PNG poster with discovery year.
- [Elements Poster 4](https://periodic-table-of-elements.top/id/printables#pdf-4): High-resolution PNG poster with electron configuration.

## Tools

- [Molar Mass Calculator](https://periodic-table-of-elements.top/id/tools/molar-mass-calculator): Compute molecular weight from chemical formulas; supports hydrates (·nH2O), nested brackets, square-bracket complexes, and standalone ion notation.
- [Equation Balancer](https://periodic-table-of-elements.top/id/tools/balance-equation): Balance chemical equations with arbitrary reactants and products using an integer-LCM algorithm; rejects unbalanceable inputs.
- [Electron Configuration Calculator](https://periodic-table-of-elements.top/id/tools/electron-configuration-calculator): Full and shorthand electron configuration for any of the 118 elements with orbital diagrams and 13 documented anomalous ground states (Cr, Cu, Mo, Pd, Au, La, Gd, ...).
- [Element Comparator](https://periodic-table-of-elements.top/id/tools/compare-elements): Side-by-side comparison of any subset of the 118 elements across atomic, thermodynamic, electrical, and abundance properties.

## Quizzes

- [Element Symbol Quiz](https://periodic-table-of-elements.top/id/quizzes/element-symbol-quiz): Multiple-choice drills matching element names to symbols. Three difficulty levels; tracks the last 10 attempts in localStorage.
- [Atomic Number Quiz](https://periodic-table-of-elements.top/id/quizzes/atomic-number-quiz): Identify an element from its atomic number and a clue. Three difficulty levels; recent-attempts history is preserved locally.
- [Category Quiz](https://periodic-table-of-elements.top/id/quizzes/category-quiz): Place elements into their periodic-table category (alkali metal, transition metal, noble gas, ...). Three difficulty levels.
- [Electron Configuration Quiz](https://periodic-table-of-elements.top/id/quizzes/electron-config-quiz): Identify elements from a partial electron configuration clue. Three difficulty levels.

## Learn

- [Apa Itu Isotop? Definisi, Contoh, dan Mengapa Itu Penting](https://periodic-table-of-elements.top/id/learn/what-are-isotopes): Penjelasan sederhana tentang isotop, notasi isotop, stabilitas, waktu paruh, dan peran isotop dalam kedokteran, arkeologi, dan energi nuklir.
- [Cara Membaca Tabel Periodik: Panduan Pemula](https://periodic-table-of-elements.top/id/learn/how-to-read-the-periodic-table): Panduan praktis tentang setiap bagian sel tabel periodik — nomor atom, simbol, massa atom, golongan, periode, blok, kategori — dengan contoh mulai dari hidrogen hingga oganeson.
- [Cara Menghafal Tabel Periodik: Simbol, Angka, dan Kategori](https://periodic-table-of-elements.top/id/learn/how-to-memorize-element-symbols): Strategi mnemonik yang terbukti untuk mempelajari simbol unsur dan nomor atom tanpa menghafal secara brute force. Pengulangan spasi, pengelompokan, dan pengenalan pola.
- [Massa Atom vs Nomor Massa: Apa Bedanya?](https://periodic-table-of-elements.top/id/learn/atomic-mass-vs-mass-number): Nomor massa menghitung nukleon individu; massa atom adalah rata-rata tertimbang di semua isotop. Panduan ini membahas keduanya, menunjukkan tampilannya dalam tabel periodik, dan menjelaskan notasi tanda kurung untuk unsur tidak stabil.
- [Mengapa Unsur Memiliki Sifat Berbeda: Hukum Periodik](https://periodic-table-of-elements.top/id/learn/why-elements-have-different-properties): Unsur yang berbeda berbeda karena konfigurasi elektronnya. Panduan ini menghubungkan jumlah proton, jumlah elektron, kulit valensi, hingga kimia, dengan contoh nyata dari seluruh tabel periodik.
- [Penjelasan Golongan Tabel Periodik: 18 Kolom dan Kimianya](https://periodic-table-of-elements.top/id/learn/periodic-table-groups-explained): Arti dari 18 golongan (kolom) tabel periodik, alasan unsur-unsur dalam golongan yang sama berperilaku serupa, dan pola masing-masing yang memungkinkan Anda memprediksi sifat kimia.
- [Penjelasan Konfigurasi Elektron: Aufbau, Kulit, dan Singkatan](https://periodic-table-of-elements.top/id/learn/electron-configuration-explained): Panduan jelas tentang notasi konfigurasi elektron, urutan pengisian Aufbau, kulit vs subkulit, dan cara membaca konfigurasi unsur apa pun dari hidrogen hingga oganeson.
- [Penjelasan Periode Tabel Periodik: 7 Baris dan Polanya](https://periodic-table-of-elements.top/id/learn/periodic-table-periods-explained): Bagaimana 7 baris horizontal (periode) tabel periodik mengkodekan jumlah kulit elektron, dan gelombang kimia yang dapat diprediksi yang berulang setiap periode.
- [Sejarah Singkat Tabel Periodik: Dari Triad hingga Oganesson](https://periodic-table-of-elements.top/id/learn/periodic-table-history): Bagaimana ahli kimia abad ke-19 memperhatikan pola berulang dalam unsur-unsur, menyusunnya menjadi tabel yang lebih baik, memperkirakan unsur-unsur yang hilang, dan sampai pada tabel 118 unsur yang kita gunakan saat ini.

## Optional

- [Sumber data](https://periodic-table-of-elements.top/id/data-sources): IUPAC, PubChem, NIST references and conflict resolution rules.
- [Full structured dump](https://periodic-table-of-elements.top/id/llms-full.txt): per-element markdown with all numeric fields.