Periodic Table of Elements
Explore all 118 elements with detailed information including atomic mass, electron configuration, category, phase, discovery year, and electronegativity. Search, filter, and compare elements. All data is embedded — nothing leaves your browser.
How to Use the Periodic Table
- Browse elements — the full periodic table is displayed with color-coded categories.
- Click an element — view detailed information including atomic mass, electron configuration, and more.
- Search or filter — find elements by name, symbol, or atomic number. Click category chips to filter.
- Compare elements — enable compare mode to select two elements and see them side-by-side.
- Copy info — copy element details to your clipboard for notes or reports.
The Periodic Table Explained
Dmitri Mendeleev published the first widely recognized periodic table in 1869, organizing elements by atomic mass and predicting the existence of undiscovered elements. The modern table arranges elements by atomic number, revealing periodic trends in properties.
Elements in the same column (group) share similar chemical properties due to having the same number of valence electrons. The table's structure reveals patterns in electronegativity, ionization energy, atomic radius, and metallic character — making it one of science's most powerful organizing tools.
Frequently Asked Questions
Elements are grouped by their electron configuration, which determines chemical behavior. Elements in the same group have the same number of valence electrons, leading to similar reactivity. For example, alkali metals (Group 1) all have one valence electron and are highly reactive.
Electronegativity (Pauling scale) measures an atom's tendency to attract bonding electrons. Fluorine is the most electronegative element (3.98). It increases across a period and decreases down a group. High electronegativity differences between bonded atoms create polar covalent bonds.
These are the two rows shown below the main table. Lanthanides (elements 57-71) are also called rare earth elements. Actinides (elements 89-103) include many radioactive elements. Both fill the f-orbital and are placed separately to keep the table compact.
Use Cases
Element Lookup
Look up element properties like atomic mass, electron configuration, and electronegativity.
Chemistry Homework
Find electron configurations and atomic masses for chemistry assignments and lab work.
Group Comparison
Identify element groups and periods to compare characteristics and reactivity patterns.
Periodic Trends
Explore trends in electronegativity, ionization energy, and atomic radius across elements.