Interactive Periodic Table – Trends, Blocks and Data for All 118 Elements
This interactive periodic table lays out all 118 elements in the standard 18-column form. Click a tile to open its data card, recolour the whole table by a property to see a periodic trend, or drag the temperature slider to see which elements are solid, liquid or gas. Every number runs in your browser, with no sign-up and no data sent anywhere.
From Mendeleev to atomic number
Dmitri Mendeleev arranged the known elements by atomic mass in 1869 and left gaps where the pattern demanded an element that had not been found yet. A few pairs, such as tellurium and iodine, only fit if the order of mass was broken. Moseley later showed that the real ordering variable is the atomic number, the number of protons, which is why the table is ordered by Z today.
Periods, groups and blocks
A period is a row: its number is the outermost electron shell being filled. A group is a column: its members share the same outer configuration, so they react alike. The blocks s, p, d and f name the subshell that is filling, and you can read all of this straight from an electron configuration. Iron, [Ar] 3d⁶ 4s², sits in period 4 because its highest shell is n = 4, and in the d-block because the 3d subshell is the one filling.
The four classic trends
Electronegativity and first ionization energy rise across a period and fall down a group. Atomic radius does the opposite. Across a period the nuclear charge grows while the electrons enter the same shell, so the pull on the outer electrons rises (see the effective nuclear charge calculator). Down a group each new shell puts the outer electron farther away.
The ionization-energy sawtooth has two famous dips. Boron and aluminium sit below beryllium and magnesium because a new p subshell starts, and a p electron is slightly easier to remove than an s electron. Oxygen and sulfur sit below nitrogen and phosphorus because the fourth p electron has to pair up, and the pairing repulsion makes it easier to lose.
The lanthanide contraction
Across the lanthanides the 4f electrons shield the growing nuclear charge poorly, so the radius barely changes from lanthanum to lutetium. The elements after them, hafnium and tantalum, come out almost the same size as zirconium and niobium above them. That is why those pairs have nearly identical chemistry and why period-6 metals are so dense.
Metals, metalloids and nonmetals
The same metal / metalloid / nonmetal split is used by the bond polarity calculator, so the two tools never disagree.
The group 3 debate
Should group 3 contain scandium, yttrium, lanthanum and actinium, or scandium, yttrium, lutetium and lawrencium? Both layouts are defensible, and IUPAC has favoured lutetium and lawrencium. This table avoids the choice by showing 15-element f-rows, La–Lu and Ac–Lr, below the main grid, with a placeholder tile in group 3 of periods 6 and 7.
Superheavy elements are predictions
Elements 104 to 118 have been made a few atoms at a time and decay in seconds or less, so their bulk properties cannot be measured. Their configurations, categories and densities are predictions from relativistic calculations, and the table colours elements 109 to 118 as having unknown properties. Elements without stable isotopes show their mass in brackets: the number is a mass number, not an average.
State at a given temperature
Choose State and move the slider to see melting and boiling points as a map. At 298 K only eleven elements are gases and just bromine and mercury are liquids. Raise the temperature a few kelvin and gallium (melting point 302.9 K) and caesium join them, which is why gallium melts in your hand. Carbon and arsenic sublime rather than melt, and helium never freezes at atmospheric pressure.
Use the compare table to line up elements side by side, then continue with the atomic mass calculator or the molar mass calculator to put the numbers to work.