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Elementarium - The Periodic Table of Elements
Explore the building blocks of the universe.
Tap an element to open its details.
About this site
Elementarium is a free educational reference built around an IUPAC-oriented periodic table. Browse every confirmed element with search and category filters, then open any tile for atomic mass, electronegativity, electron configuration, discovery context, and more. Below the table you can jump to an interactive atom builder to explore protons, neutrons, and electrons, read a visual timeline of chemistry milestones, and review chemistry basics that connect simple shell ideas with orbitals. The experience is available in nine languages, requires no account, and is written for students, teachers, and curious readers who want clear, classroom-friendly explanations next to the data.
Build your atom
Add protons, neutrons, and electrons to see how the atom and element change.
Build your atomThe History of the Periodic Table
The periodic table of elements is one of the most important achievements in modern chemistry. It organizes all known chemical elements by their atomic number, electron configuration, and recurring chemical properties. From ancient civilizations recognizing gold and silver to scientists synthesizing new elements in laboratories, the story of the periodic table spans millennia of human discovery and scientific advancement.
Key Milestones in Periodic Table History
Pre-1669
Ancient Elements
Humans have known about gold, silver, copper, iron, lead, tin, mercury, sulfur, and carbon since ancient times. These elements were used for tools, currency, and art long before chemistry emerged as a science.
1669
Phosphorus Discovered
Hennig Brand discovered phosphorus, becoming the first person in history to discover a new chemical element. This marked the beginning of the age of modern element discovery.
1789
First Chemical Classification
Antoine Lavoisier published the first modern list of chemical elements, defining an element as a substance that cannot be broken down by existing chemical means. He identified 33 elements.
1864-1865
Law of Octaves
John Newlands proposed that when elements were arranged by atomic weight, every eighth element had similar properties. Though initially ridiculed, his work laid groundwork for the periodic law.
1869
Mendeleev's Periodic Table
Dmitri Mendeleev published the first widely recognized periodic table, arranging 63 known elements by atomic weight and chemical properties. He famously left gaps for undiscovered elements.
1913
Atomic Number Discovery
Henry Moseley discovered that atomic number (nuclear charge) rather than atomic mass determines an element's position in the periodic table, explaining previous anomalies.
1940+
Synthetic Elements Era
Scientists began creating new transuranium elements in laboratories. Neptunium and plutonium were the first synthetic elements beyond uranium, extending the table past atomic number 92.
Today
The Complete Table
The periodic table now contains 118 confirmed elements, with the latest additions being nihonium, flerovium, moscovium, livermorium, tennessine, and oganesson in 2016.
Pre-1669
Ancient Elements
1669
Phosphorus Discovered
1789
First Chemical Classification
1864-1865
Law of Octaves
1869
Mendeleev's Periodic Table
1913
Atomic Number Discovery
1940+
Synthetic Elements Era
Today
The Complete Table
Pre-1669
Ancient Elements
Humans have known about gold, silver, copper, iron, lead, tin, mercury, sulfur, and carbon since ancient times. These elements were used for tools, currency, and art long before chemistry emerged as a science.
1669
Phosphorus Discovered
Hennig Brand discovered phosphorus, becoming the first person in history to discover a new chemical element. This marked the beginning of the age of modern element discovery.
1789
First Chemical Classification
Antoine Lavoisier published the first modern list of chemical elements, defining an element as a substance that cannot be broken down by existing chemical means. He identified 33 elements.
1864-1865
Law of Octaves
John Newlands proposed that when elements were arranged by atomic weight, every eighth element had similar properties. Though initially ridiculed, his work laid groundwork for the periodic law.
1869
Mendeleev's Periodic Table
Dmitri Mendeleev published the first widely recognized periodic table, arranging 63 known elements by atomic weight and chemical properties. He famously left gaps for undiscovered elements.
1913
Atomic Number Discovery
Henry Moseley discovered that atomic number (nuclear charge) rather than atomic mass determines an element's position in the periodic table, explaining previous anomalies.
1940+
Synthetic Elements Era
Scientists began creating new transuranium elements in laboratories. Neptunium and plutonium were the first synthetic elements beyond uranium, extending the table past atomic number 92.
Today
The Complete Table
The periodic table now contains 118 confirmed elements, with the latest additions being nihonium, flerovium, moscovium, livermorium, tennessine, and oganesson in 2016.
Chemistry Basics
Understand the fundamental concepts of chemistry - from atomic structure and the periodic table to different types of chemical bonds.
Atomic Structure
Atoms are the smallest units of chemical elements and consist of a nucleus and an electron shell.
- The atomic nucleus contains protons (positively charged) and neutrons (neutral)
- The electron shell consists of negatively charged electrons
- The number of protons determines the element (atomic number)
Protons, Neutrons, Electrons
These three particles are the fundamental building blocks of every atom and have different properties.
p⁺Proton
n⁰Neutron
e⁻Electron
Isotopes
Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.
Example: Carbon isotopes
C126
Stable (98.9%)
C146
Radioactive
Two ways to picture electrons:
the Bohr model and simplified orbital view
The Bohr model (Niels Bohr, 1913) pictures electrons on circular orbits (shells) around the nucleus, like planets. Each shell has a principal quantum number n (n = 1, 2, 3, …) and a fixed energy. This view is good for intuition and the idea of energy levels, but it is simplified: it does not explain subshells (s, p, d, f), chemical bonding, or line spectra in detail. Electrons do not actually follow classical paths.
The orbital (quantum-mechanical) model describes electrons by wave functions; we do not have literal paths. Orbitals are regions where the electron is found with high probability. Subshells have characteristic shapes: s (spherical), p (three dumbbells along x, y, z), d (five lobes), f (seven lobes). Notation such as 1s² 2s² 2p⁶ is used in the element details. This is the correct framework for chemistry and the periodic table.