Skip to content

A space we build together

MOA
Log in

Periodic table (names, atomic mass, electron configuration)

Browse all 118 elements: name, atomic mass, metal / metalloid / nonmetal class, group and period, electron configuration, melting and boiling points. Click an element for its electron configuration and shell diagram.

Atomic masses are abridged IUPAC standard values; a value in parentheses is the mass number of the longest-lived isotope, used when an element has no stable isotope. Electronegativity is on the Pauling scale; melting and boiling points are at 1 atm, left blank where uncertain or where pressure is needed. Most properties of elements above 103 are predicted, as only a few atoms have ever been made.

FAQ

Is a metalloid a metal or a nonmetal?
Something in between. Boron, silicon, germanium, arsenic, antimony and tellurium are the usual ones, and they are widely used in semiconductors. Sources draw the line slightly differently; this tool uses those six.
What does a notation like [Ar] mean in an electron configuration?
It stands for the electron configuration of that noble gas (argon here), written in place of the inner shells. The detail view also shows the full, unabbreviated configuration.
Why do chromium and copper break the filling rule?
A half-filled or completely filled d subshell is slightly more stable. Chromium (3d⁵ 4s¹) and copper (3d¹⁰ 4s¹) are the classic cases; a few other transition metals, lanthanides and actinides are exceptions too, and the detail view marks them.
What do the parentheses around an atomic mass mean?
The element has no stable isotope, so no standard atomic weight exists. The mass number of its longest-lived isotope is shown instead.

How to use this tool

Use it to browse the periodic table or look up an element's properties and origin. Pick an element to see an electron-shell animation and notes on its history, name origin, properties and uses below. Nothing is sent to a server.

Frequently asked questions

What can I learn by picking an element?

Its atomic number, symbol, atomic mass and category, plus an electron-shell animation and notes on its history, name origin, properties and uses.

How many elements are there?

118 elements arranged by atomic number; groups (columns) and periods (rows) bring together elements with similar properties.

Is anything sent to a server?

No. The periodic table runs only in this browser and sends nothing to a server.

See all tools

Unit converter

Convert length, weight, temperature, area and volume, including traditional Korean units such as pyeong, geun, don and ja.

Exchange rates & alerts

Convert between major currencies at the Korea Eximbank base rates, and get an email when a rate you care about is reached.

Color Converter

Convert HEX, RGB, CMYK and HSL color codes to each other, and check text/background contrast (WCAG) and palette combinations.

Quote & statement maker

Enter your items to get a document preview with supply value, VAT and total (with the amount in Korean words), then print it or save it as a PDF. Nothing you enter is sent to a server.

Salary & Payroll Calculator

Take-home pay after Korean social insurance and income tax, weekly-holiday allowance, severance pay and unemployment benefit. Uses that year's rates; nothing you enter leaves this browser.

Real Estate Calculators

Korean brokerage fee caps, home acquisition tax, jeonse-monthly rent conversion and LTV/DSR loan limits. Reference calculations using that year's rules; nothing you enter leaves this browser.