Interactive reference for all 118 chemical elements
The periodic table is one of the most powerful organizational tools in all of science. First devised by Dmitri Mendeleev in 1869, it arranges all known chemical elements in order of increasing atomic number and groups them into rows (periods) and columns (groups) based on recurring patterns in their physical and chemical properties. Today the table contains 118 confirmed elements — from the lightest, hydrogen (atomic number 1), to the most recently confirmed, oganesson (atomic number 118, synthesized in 2002). Every student of chemistry, biology, physics, geology, medicine, and materials science relies on the periodic table as a fundamental reference. This interactive periodic table gives you instant access to detailed data for every element. Click any element cell to open its full property panel, showing atomic mass, electron configuration, melting and boiling points, electronegativity, ionization energy, density, oxidation states, discovery history, biological role, and more. Use the search bar to find any element instantly by name, symbol, or atomic number. Filter by element category — alkali metals, transition metals, noble gases, lanthanides, actinides, and more — to highlight groups of related elements. The temperature slider lets you visualize which elements are solid, liquid, or gas at any temperature from near absolute zero to 6000 K. The periodic table is organized into 18 vertical groups and 7 horizontal periods. Elements in the same group share similar chemical behavior because they have the same number of valence electrons — the outermost electrons that govern bonding. For example, Group 1 (alkali metals) all react vigorously with water; Group 18 (noble gases) are all chemically inert under ordinary conditions. The f-block elements — lanthanides (periods 6, groups 3) and actinides (period 7, group 3) — are displayed in two rows below the main table for compactness, even though they logically belong between groups 2 and 4 in periods 6 and 7. The property heat-map feature provides a powerful way to visualize trends across all 118 elements simultaneously. Select any property — electronegativity, ionization energy, atomic mass, density, melting point, boiling point, atomic radius, electron affinity, discovery year, or crustal abundance — and the entire table changes color from blue (low values) through yellow to red (high values). This makes periodic trends immediately visible: for example, electronegativity increases left-to-right and bottom-to-top; atomic radius increases right-to-left and top-to-bottom; and ionization energy follows a complex but discernible pattern reflecting electron shell filling. The molar mass builder lets you construct any chemical formula by clicking elements and entering subscripts. The tool automatically calculates the molar mass in grams per mole, which is essential for stoichiometry calculations in chemistry labs. You can also solve the m = nM equation (mass = moles × molar mass) — enter any two values and instantly find the third. This makes the tool useful for students preparing for chemistry exams, lab technicians preparing solutions, and anyone needing quick molar mass data. Element data in this tool is sourced from IUPAC (International Union of Pure and Applied Chemistry) 2021 atomic weight values and standard reference data. Properties like melting point, boiling point, density, electronegativity, and ionization energy are given at standard conditions (STP: 0°C, 1 atm) unless otherwise noted. Radioactive elements with no stable isotopes display their most stable isotope mass number in brackets (e.g., [277] for copernicium). Synthetic elements with atomic numbers 104–118 are clearly indicated, as they have extremely short half-lives and exist only in particle accelerator experiments. Whether you are a high school student learning the elements for the first time, an undergraduate studying inorganic or physical chemistry, a professional chemist needing quick property look-ups, or simply a curious person who wants to explore the building blocks of matter, this interactive periodic table has everything you need. Bookmark it as your go-to chemistry reference for quick, accurate, ad-light element data.
Understanding the Periodic Table
What Is the Periodic Table?
The periodic table is a tabular arrangement of the 118 known chemical elements, organized by atomic number (number of protons), electron configuration, and recurring chemical properties. Elements are placed in rows called periods (1–7) and columns called groups (1–18). The table is divided into four blocks named after the atomic orbital being filled: s-block (groups 1–2 + helium), p-block (groups 13–18 minus helium), d-block (groups 3–12, transition metals), and f-block (lanthanides and actinides). This arrangement reveals the periodic law: the physical and chemical properties of elements are periodic functions of their atomic numbers. Mendeleev's original 1869 table predicted the existence and properties of elements not yet discovered — a triumph of scientific pattern recognition that cemented the periodic table as a cornerstone of chemistry.
How Are Element Properties Determined?
Atomic mass is the weighted average of all naturally occurring isotopes of an element, measured in unified atomic mass units (u or Da). Electronegativity (Pauling scale) measures an atom's ability to attract electrons in a covalent bond — fluorine has the highest value (3.98) and cesium one of the lowest (0.79). Ionization energy is the minimum energy required to remove an electron from a gaseous atom — it generally increases across a period (left to right) and decreases down a group (top to bottom). Melting and boiling points are measured experimentally and reflect the strength of interatomic/intermolecular forces. Electron configurations follow the Aufbau principle (filling from lowest to highest energy), the Pauli exclusion principle (two electrons per orbital with opposite spins), and Hund's rule (maximum multiplicity in degenerate orbitals), with notable exceptions for Cr, Cu, Pd, and others.
Why Does the Periodic Table Matter?
The periodic table underpins virtually all of chemistry, materials science, pharmacology, geology, and nuclear physics. Understanding which group an element belongs to immediately predicts its valence, typical oxidation states, reactivity, and the types of compounds it forms. This knowledge drives drug design (knowing which elements are bioavailable and non-toxic), materials engineering (choosing metals, semiconductors, or insulators), environmental science (understanding which elements bioaccumulate or are toxic), and nuclear technology (actinide chemistry for reactor fuels and medical isotopes). The periodic table also encodes the story of cosmological nucleosynthesis — elements up to iron are forged in stellar cores; heavier elements form in supernova explosions and neutron star mergers. Every atom in your body except hydrogen was created in a star.
Data Accuracy and Limitations
Element data in reference tools like this one reflects accepted values under standard conditions (20°C, 1 atm) and may differ in extreme environments. Properties of synthetic elements (Z ≥ 104) are often estimated or known only from a few atoms; their melting points, boiling points, and densities are largely theoretical. Electron configurations of some d- and f-block elements deviate from simple Aufbau predictions due to relativistic effects and electron-electron repulsion. Electronegativity values do not exist for noble gases under normal definitions. Atomic masses of radioactive elements are given for their most stable isotope. Crustal abundance data refers to Earth's continental crust and does not represent the full Earth or ocean floor. Always cross-reference with primary literature (IUPAC, NIST) for research applications.
How to Use the Periodic Table
Click an Element for Full Details
Tap or click any element cell in the periodic table grid to open its detail panel. You'll see the full property set: atomic mass, electron configuration, melting and boiling points, electronegativity, density, oxidation states, ionization energy, discovery information, biological role, and common uses.
Search and Filter Elements
Use the search bar to instantly find any element by name, chemical symbol, or atomic number. Use the category filter buttons to highlight groups — for example, select 'Transition Metal' to see all d-block metals, or 'Noble Gas' to highlight the Group 18 elements. Non-matching elements are dimmed so the pattern is immediately visible.
Use the Temperature Slider
Drag the temperature slider (0–6000 K) to visualize the state of matter (solid, liquid, or gas) for every element at that temperature. Watch elements transition as temperature rises — at 1000 K you'll see some metals liquefied while others remain solid. Useful for understanding phase behavior across the table at a glance.
Visualize Property Trends with the Heat Map
Select a property from the 'Color by property' dropdown — such as electronegativity, ionization energy, or density — to color-code the entire table from blue (low) to red (high). This instantly reveals periodic trends. You can also use the Molar Mass Builder at the bottom: click elements or type a formula (e.g., H2O) to calculate the molar mass and percentage composition.
Frequently Asked Questions
How many elements are in the periodic table?
As of 2024, the periodic table contains 118 confirmed chemical elements, from hydrogen (atomic number 1) to oganesson (atomic number 118). Elements 1 through 94 occur naturally on Earth in at least trace amounts; elements 95 through 118 are entirely synthetic and can only be produced in nuclear reactors or particle accelerators. The heaviest naturally occurring element is plutonium (Z=94), though traces of neptunium (Z=93) and plutonium are found in uranium ores. IUPAC officially confirmed elements 113 (nihonium), 115 (moscovium), 117 (tennessine), and 118 (oganesson) in January 2016, completing period 7 of the table. Researchers are actively attempting to synthesize element 119 and beyond, which would begin period 8.
What do the element categories (colors) mean?
The 10 color-coded categories reflect the fundamental classification of elements by their properties. Alkali metals (Group 1) are highly reactive soft metals. Alkaline earth metals (Group 2) are reactive but less so than alkali metals. Transition metals (Groups 3–12) are the familiar hard metals: iron, copper, gold, silver. Post-transition metals (e.g., aluminum, lead, tin) are softer and more electronegative than transition metals. Metalloids (e.g., silicon, germanium) have mixed metallic/nonmetallic properties and are crucial as semiconductors. Reactive nonmetals (e.g., carbon, nitrogen, oxygen, sulfur) form the chemical basis of life. Halogens (Group 17) are reactive nonmetals that readily form salts. Noble gases (Group 18) are chemically inert. Lanthanides and actinides are the f-block elements, with special magnetic and nuclear properties.
What is electron configuration and why does it matter?
Electron configuration describes how electrons are distributed among the atomic orbitals of an atom. It is written using shell numbers (1, 2, 3...) and orbital subshell letters (s, p, d, f) with superscript counts — for example, carbon is 1s² 2s² 2p² (6 electrons total). The shorthand version uses the previous noble gas in brackets: [He] 2s² 2p². Electron configuration determines virtually all chemical behavior: the number of valence electrons (outermost shell) controls bonding capacity, oxidation states, and reactivity. Elements in the same group have the same valence electron configuration (just in higher shells), which is why they share similar chemical properties. Understanding electron configuration is essential for predicting which elements will bond together, what types of bonds they form, and the shapes and properties of the resulting molecules.
What are periods and groups in the periodic table?
Periods are the horizontal rows in the periodic table, numbered 1 through 7. Each period corresponds to one electron shell being filled; period 1 fills the 1s orbital (H and He), period 2 fills the 2s and 2p orbitals (Li through Ne), and so on. Moving across a period, each successive element has one more proton and one more electron. Groups are the vertical columns, numbered 1 through 18. Elements in the same group share the same number of valence electrons, giving them similar chemistry. For instance, all Group 1 elements (alkali metals) have 1 valence electron and react vigorously with water; all Group 17 elements (halogens) have 7 valence electrons and readily gain one more to form anions. The period and group together uniquely identify an element's position and predict its behavior.
How do I use the molar mass builder?
The molar mass builder lets you calculate the molar mass of any chemical compound. Type a formula directly into the formula field (e.g., H2O, C6H12O6, Fe2O3, Ca(OH)2) — the tool parses subscripts, parentheses, and nested groups automatically and instantly displays the molar mass in grams per mole plus the percentage composition by element. You can also click element cells in the table to add them to the formula. To solve for mass, moles, or molar mass using the m = nM equation, enter any two of the three values and the tool calculates the third. This is useful for lab work: if you know you need 0.5 mol of sodium chloride (NaCl, molar mass 58.44 g/mol), the tool tells you to weigh out 29.22 g.
What does the temperature slider show?
The temperature slider (range: 0 K to 6000 K) visualizes the state of matter for every element at the selected temperature. As you drag the slider upward, elements transition from solid to liquid (at their melting point) and from liquid to gas (at their boiling point). At 293 K (room temperature, 20°C), most elements are solid; only two — mercury (Hg) and bromine (Br) — are liquid; and a handful — H, N, O, F, Cl, and all noble gases — are gases. At very high temperatures (above ~4000 K) almost all elements are gases. The color coding changes in real time: gray for solid, blue for liquid, orange/red for gas, and a lighter shade for elements with unknown phase data. This slider is especially useful for understanding metallurgy and the behavior of elements in extreme environments like stellar interiors or industrial furnaces.