Interactive Periodic Table & Property Trends

What it is for

The periodic table is arranged so that properties change in a regular way: across a period atoms get smaller and hold on to their electrons more tightly, and down a group the opposite happens. Textbooks show this with a few arrows. This tool shows the actual numbers for all 118 elements as a heatmap, so you can see where the pattern holds and where it breaks.

Pick a property (electronegativity, van der Waals radius, first ionisation energy, electron affinity, melting and boiling point, density, atomic weight, year of discovery, or a category such as block, state or element family). The tool colours every element, names the highest and lowest value, and can list a whole period or group as a trend chart. Add up to twelve elements to get their full data side by side.

The values come from the PubChem periodic table, which compiles them from NIST, Los Alamos and Jefferson Lab. Atomic weights are the IUPAC (CIAAW) standard values. It is a reference and teaching tool, not a database of measured values for your sample.

Worked example

Choose Electronegativity, enter F as the element and set the trend to period 2. The summary reads: highest F (3.98), lowest Fr (0.7); F has 3.98. Fluorine ranks 1 of the 95 elements that have a Pauling value. The trend table climbs steadily from lithium 0.98 through beryllium 1.57, boron 2.04, carbon 2.55, nitrogen 3.04 and oxygen 3.44 to fluorine. Neon has no value, because noble gases form almost no bonds. 23 elements are grey for that reason or because they have never been made in weighable amounts.

Now switch to First ionisation energy and group 1. Helium is highest at 24.587 eV, caesium lowest at 3.894 eV. Down the alkali metals the energy falls from lithium 5.392 eV to caesium 3.894 eV. Francium is slightly higher than caesium again, a relativistic effect worth pointing out to students.

How to read the result

• The heatmap uses a colour-blind-safe scale from dark (low) to bright (high). Grey means no data. For properties that span many orders of magnitude, such as density, the scale switches to logarithmic automatically. You can force a linear scale.
• Highest and lowest value and the rank of your element tell you where it sits among all elements with data.
• The trend chart plots one period or group in order of atomic number. Gaps are missing values.
• The comparison table lists every property of the chosen elements, including configuration and oxidation states.

Tips and common mistakes

• Atomic radius has several definitions. These are van der Waals radii, so sodium is 227 pm here, while covalent radius tables list about 166 pm.
• Electronegativity is the Pauling scale. Other scales (Allen, Mulliken) give different numbers but similar trends.
• Melting points and densities of the heaviest elements are often predictions, so treat them with care.
• Category colours follow the common textbook families. Where hydrogen belongs is a convention.
• In the Proofline Element Lab view (key 5) you can click through the table and print it as a PDF poster.

FAQ

Why do some elements have no value?

Elements beyond about Z = 100 exist only a few atoms at a time, so properties like density or melting point have never been measured. Noble gases have no Pauling electronegativity.

Where do the values come from?

From the PubChem periodic table (NCBI), which compiles NIST, Los Alamos and Jefferson Lab data. Atomic weights are the CIAAW standard atomic weights. The sources are listed with every result.

Can I compare more than two elements?

Yes, up to twelve, separated by commas: Fe, Cu, Au.

Why is the highest density osmium and not iridium?

With the values used here osmium is 22.57 g/cm³. The two are within a fraction of a percent, and the order depends on the crystal data used.