Interactive Periodic Table Explorer

Color the whole table by any property to see periodic trends at a glance, slide the temperature to watch elements melt and boil, or click any element for its electron configuration, Bohr shell diagram, and full property list.

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Why the table has its shape 🖖

The periodic table isn't an arbitrary grid — its shape is dictated by how electrons fill up quantum shells and subshells. Each row (period) corresponds to a new outer electron shell being filled, and each column (group) collects elements whose outermost shell has the same number of electrons. Because chemical behaviour is governed almost entirely by those outer (valence) electrons, elements stacked in the same column behave alike: the alkali metals are all soft and violently reactive, the noble gases are all inert. The two-column s-block, six-column p-block, ten-column d-block, and fourteen-column f-block widths are exactly the 2, 6, 10, and 14 electrons that s, p, d, and f subshells can hold. Read the table as a map of electron structure and the trends stop being facts to memorize and become consequences you can predict.

Reading a trend off the colors 🖖

Switch to a property heatmap and the periodic trends jump out as color gradients. Atomic radius shrinks left-to-right across a period (the growing nuclear charge pulls the same shell inward) and grows down a group (each period adds a whole new shell). Electronegativity and ionization energy do the opposite — rising toward the top-right, peaking at fluorine and helium, because a small atom with a nearly full shell grips its electrons hardest. Once you can see one trend, you can predict the others: they all trace back to how far the outer electrons sit from the nucleus and how strongly they are held.

The table as a thermometer 🖖

The State at T mode turns the table into a thermometer. Every element has a melting point and a boiling point, so at any temperature you choose, each element is solid, liquid, or gas. At room temperature (298 K) only two elements are liquid — mercury and bromine — and eleven are gases; almost everything else is a solid metal. Slide toward the extremes and the pattern reorganizes: near absolute zero even hydrogen and helium freeze, while above a few thousand kelvin the refractory metals like tungsten (melting at 3695 K) are the last solids standing. It's a vivid reminder that 'solid', 'liquid', and 'gas' are not properties of a substance but of a substance at a temperature.

A table that predicts the future 🖖

When Dmitri Mendeleev arranged the elements in 1869 he did something audacious: he left gaps and predicted the properties of elements nobody had found yet. He described "eka-silicon" — later discovered and named germanium — down to its density, melting behaviour, and oxide formula, and did the same for gallium and scandium, years before anyone isolated them. When they turned up matching his numbers, the periodic law went from a curiosity to a law of nature. That predictive power still works: the same periodic logic guides today's hunt for superheavy elements and the theorized "island of stability" beyond the current edge of the table. The empty and gray squares aren't blanks — they're a to-do list for physics.

Periodic trends explained

The periodic table organizes elements so that recurring (periodic) patterns line up into columns and rows. These are the trends every chemistry student is expected to know — and each one falls straight out of electron structure.

Atomic radius

r: → decreases · ↓ increases

Atomic radius decreases across a period from left to right, because each added proton increases the nuclear charge pulling on electrons that are all in the same shell. It increases down a group, because each new period adds an entirely new, larger electron shell. Caesium and francium are among the largest atoms; helium is the smallest.

Electronegativity

χ: → increases · ↓ decreases (max: F = 3.98)

Electronegativity — an atom's pull on shared bonding electrons — increases across a period and decreases down a group, mirroring atomic radius in reverse. Fluorine is the most electronegative element (3.98 on the Pauling scale); the alkali metals at the bottom-left are the least. Large electronegativity differences between two bonded atoms produce ionic bonds; small differences give covalent bonds.

Ionization energy

IE₁: → increases · ↓ decreases

First ionization energy is the energy needed to remove the outermost electron. It rises across a period (electrons are held more tightly by the growing nuclear charge) and falls down a group (outer electrons are farther from the nucleus and shielded by inner shells). Noble gases sit at the peaks; alkali metals at the valleys, which is why alkali metals lose an electron so easily to form +1 ions.

Electron affinity

EA: highest at the halogens

Electron affinity is the energy released when an atom gains an electron. Halogens have the highest values — chlorine tops the list — because adding one electron completes their outer shell. Noble gases have essentially zero affinity: their shells are already full, so an extra electron would have to start a new, high-energy shell.

Metallic character

metallic character: → decreases · ↓ increases

Metallic character — the tendency to lose electrons and form positive ions — increases down a group and decreases across a period, the opposite of electronegativity. The most metallic elements sit at the bottom-left; the most nonmetallic at the top-right. The metalloids (boron, silicon, germanium, arsenic, antimony, tellurium) form a diagonal staircase marking the fuzzy border between metals and nonmetals.

s, p, d, and f blocks

s=2 · p=6 · d=10 · f=14 electrons

The table is divided into blocks by which subshell is being filled. The 2-wide s-block and 6-wide p-block make up the main-group elements; the 10-wide d-block holds the transition metals; and the 14-wide f-block — the lanthanides and actinides — is pulled out below the table to keep it readable. The block widths are exactly the electron capacities of the s (2), p (6), d (10), and f (14) subshells.

The element families

Coloring the table by family groups elements that behave alike. Here is what each color means.

Alkali metal — Soft, silvery, extremely reactive metals with one valence electron; they react vigorously with water.
Alkaline earth metal — Reactive metals with two valence electrons; harder and less reactive than the alkali metals.
Transition metal — Hard, dense metals that form colored compounds and multiple oxidation states; they fill the d-subshell.
Post-transition metal — Softer metals to the right of the transition block, such as aluminium, tin, and lead.
Metalloid — Elements along the staircase with in-between properties; silicon and germanium are the basis of semiconductors.
Reactive nonmetal — Reactive nonmetals including the building blocks of life — carbon, nitrogen, oxygen, phosphorus, and sulfur.
Halogen — Highly reactive nonmetals of group 17 that readily gain one electron to form −1 ions and salts.
Noble gas — Inert gases of group 18 with full outer shells; they rarely react at all.
Lanthanide — The 4f-block rare-earth metals, essential to magnets, lasers, and phosphors.
Actinide — The 5f-block metals, all radioactive, including uranium and plutonium.
Unknown properties — Superheavy synthetic elements whose chemical properties are predicted but not yet fully measured.

Frequently asked questions

How do you read the periodic table?

Read it left to right, top to bottom, in order of increasing atomic number (the number of protons). Each row is a period and each column is a group. Elements in the same group share the same number of outer-shell electrons and therefore behave chemically alike. An element's box shows its atomic number, symbol, and atomic mass.

What is an electron configuration?

An electron configuration lists how an atom's electrons are distributed among its shells and subshells, for example carbon is 1s² 2s² 2p². It follows the aufbau principle — electrons fill the lowest-energy subshells first. This tool shows the noble-gas shorthand configuration and a Bohr shell diagram for every element.

Why do periodic trends happen?

Because chemical behaviour is controlled by the outermost electrons and how strongly the nucleus holds them. Moving across a period adds protons without adding a new shell, so atoms get smaller and hold electrons more tightly. Moving down a group adds whole new shells, so atoms get bigger and hold their outer electrons more loosely.

What is the difference between a group and a period?

A group is a vertical column (there are 18) and a period is a horizontal row (there are 7). Groups gather elements with similar chemistry; periods track the progressive filling of a new electron shell. The number at the top of a main-group column equals the count of valence electrons.

Where are the metals and nonmetals?

Metals fill the left and center of the table — the vast majority of elements. Nonmetals cluster at the top-right, with the noble gases in the last column. A diagonal staircase of metalloids (boron, silicon, germanium, arsenic, antimony, tellurium) separates the two, showing gradually blended properties.

Which elements are liquid at room temperature?

Only two elements are liquid at 25 °C (298 K): mercury and bromine. Gallium and caesium melt just above room temperature (around 30 and 28 °C). Use the State at T mode to see how the count of solids, liquids, and gases changes as you raise or lower the temperature.