Periodic Table

This periodic table is an interactive reference covering the first 36 elements, hydrogen through krypton. Each element sits in its correct group and period, colour-coded by category, and clicking a tile opens a card with its physical and atomic properties. It is built for quick lookups and classroom demonstration rather than as a replacement for a full 118-element reference.

What the Table Covers

The 36 elements on display span four periods and all eight main groups, plus the first row of transition metals:

• Period 1: hydrogen and helium.
• Period 2: lithium through neon.
• Period 3: sodium through argon.
• Period 4: potassium through krypton, including the transition series scandium to zinc.

That range includes every element category the tool recognises: alkali metals, alkaline earth metals, transition metals, post-transition metals, metalloids, nonmetals, halogens, and noble gases. If you need an element above krypton, this table will not have it.

Finding an Element Fast

The search field filters the grid in real time as you type. Because matching is substring-based across three fields, you can reach an element three different ways:

You type	It matches
Fe	Iron, by exact symbol
iron	Iron, by name
26	Iron, by atomic number
n	Any name or symbol containing the letter n, such as nitrogen, neon, and manganese

Clear the field to restore the full table. The category colours remain visible while a filter is active, so you can still see where the matching elements sit in the layout.

Reading an Element Card

Take iron as an example. Clicking its tile shows:

Property	Value
Symbol / name	Fe / Iron
Atomic number	26
Atomic mass	55.845
Category	transition metal
Group / period	8 / 4
Electron configuration	[Ar] 3d⁶ 4s²
Electronegativity	1.83
Melting point	1538 °C
Boiling point	2861 °C
Density	7.874 g/cm³
Year discovered	blank (known since antiquity)

The electron configuration uses the noble-gas shorthand, so [Ar] stands for the argon core. The blank discovery year is significant: iron, carbon, sulfur, copper, and zinc have null there because they were in use long before anyone recorded a discovery, whereas elements such as gallium carry a concrete year (1875).

Periodic Trends You Can See

The first 36 elements are enough to observe several patterns directly:

• Electronegativity rises from left to right across a period and falls down a group. Fluorine tops this table at 3.98; potassium sits at the bottom with 0.82.
• Metallic character increases down and to the left, which is why the left column holds reactive alkali metals and the right column holds nonmetals and noble gases.
• Melting points vary enormously. Helium melts at -272.2 °C, the lowest in the set, while carbon’s listed melting point of 3550 °C is the highest. Gallium is the outlier that melts at 29.76 °C, just below body temperature, so a gallium spoon liquefies in a warm hand.
• Density separates gases from solids by orders of magnitude: hydrogen is 0.00008988 g/cm³ as a gas, while copper is 8.96 g/cm³.

Group and Period, Decoded

Every element card lists a group and a period, and those two numbers explain most of an element’s chemistry. The period is the horizontal row and corresponds to the principal electron shell being filled. The group is the vertical column, and for main-group elements it tells you how many valence electrons the element has.

Walking through a few entries shows the pattern:

• Sodium is group 1, period 3, with configuration [Ne] 3s¹. One valence electron outside a neon core makes it a reactive alkali metal that readily loses that electron.
• Chlorine is group 17, period 3, with [Ne] 3s² 3p⁵. Seven valence electrons and a strong pull toward one more make it a halogen that readily gains an electron.
• Iron is group 8, period 4, with [Ar] 3d⁶ 4s². Its partly filled d shell is why transition metals show variable oxidation states and coloured compounds.
• Helium is the exception worth remembering: it is in group 18 with the noble gases, but it sits in period 1 with just 1s², a full shell of two electrons rather than eight.

Reading the group number as a valence count works for the main groups but not for the transition series, where the d electrons complicate things.

Data Caveats

• The table is truncated at 36 elements. Do not read the absence of an element as evidence about its properties.
• Temperatures are in degrees Celsius and densities are in grams per cubic centimetre, but the card does not restate the units, so confirm before publishing a value.
• Some boiling points depend on pressure, and a few elements sublime or decompose before boiling. Arsenic, as noted above, is the clearest example in this set.
• Values are rounded to a few significant figures for readability. Use a full data source when you need high-precision atomic masses.

Use Cases

• Chemistry homework and revision, where a quick property lookup beats flipping through a textbook index.
• Teaching periodic trends by pointing at the live colour pattern rather than a static chart.
• Cross-checking a value such as a melting point or electron configuration before citing it.
• Satisfying curiosity about the elements you encounter in daily life, from the gallium in a lab demo to the argon in a light bulb.

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