OneTaskBy Tim King · Updated
Interactive Periodic Table of the Elements
All 118 Elements With Atomic Mass, Electron Configuration and Electronegativity
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How the Interactive Periodic Table works
An interactive periodic table of all 118 elements. Tap any element to see its atomic number, atomic mass, category, group and period, electron configuration, Pauling electronegativity and state at room temperature. Colour the table by category, block, state, electronegativity or mass, click a legend entry to pick out one family, or type a name, symbol or number to find an element.
The periodic table arranges the elements in order of atomic number, the number of protons in the nucleus, wrapped into rows so that elements with similar chemistry sit in the same column. That one layout explains a great deal: the alkali metals down the left all react violently with water, the noble gases on the right barely react at all, and electronegativity rises towards fluorine in the top right corner.
How to read the periodic table
Each row is a period, and each period starts filling a new electron shell. Each column is a group, numbered 1 to 18, and elements in a group have the same number of outer electrons, which is why they behave alike. The blocks show which subshell is filling: the s-block is groups 1 and 2 plus helium, the p-block is groups 13 to 18, the d-block holds the transition metals in the middle and the f-block holds the lanthanides and actinides, drawn as two rows underneath so the table fits on a page.
What the numbers mean
The atomic mass is the average mass of an atom in unified atomic mass units, weighted by the natural mix of isotopes. It is also the mass in grams of one mole of the element, which is why it is the starting point for every molar mass and stoichiometry sum. Elements with no stable isotopes show the mass number of their longest-lived isotope in square brackets, such as [98] for technetium.
The electron configuration lists the occupied subshells in noble-gas shorthand, so iron is [Ar] 4s2 3d6: the argon core plus two electrons in 4s and six in 3d. A few elements, including chromium, copper, silver and gold, break the usual filling order because a half-full or full d subshell is more stable, and the table shows their real ground states.
Electronegativity on the Pauling scale measures how strongly an atom pulls shared electrons towards itself, from 0.79 for caesium to 3.98 for fluorine. The difference between two atoms predicts the bond: under about 0.4 is non-polar covalent, up to about 1.7 is polar covalent and beyond that the bond is mostly ionic. The noble gases helium, neon and argon have no measured value.
Tips for using the table
- Link straight to an element. The address updates as you pick, so periodic-table#Au opens on gold.
- Use the colour modes for trends. Colour by electronegativity to see the diagonal rise towards fluorine, or by state to spot the only two liquids, mercury and bromine.
- Click a legend entry to fade everything else, which makes it easy to count the metalloids or find every halogen.
- Masses are rounded to the precision used in school and university courses. For high-precision work use the IUPAC tables directly.
FAQ
How many elements are on the periodic table?
There are 118 confirmed elements, from hydrogen with one proton to oganesson with 118. The first 94 occur naturally on Earth, at least in traces, and the rest have only been made in laboratories, often a few atoms at a time. The seventh row was completed in 2016 when nihonium, moscovium, tennessine and oganesson were named.
Why are the lanthanides and actinides shown separately?
They belong in periods 6 and 7 between groups 2 and 3, where they fill the 4f and 5f subshells. Put in line, the table would be 32 columns wide and hard to print or read, so the two rows of 15 are drawn underneath and their place in the main table is marked with the number ranges 57–71 and 89–103.
What is the most electronegative element?
Fluorine, at 3.98 on the Pauling scale, followed by oxygen at 3.44 and chlorine at 3.16. That is why fluorine compounds are so reactive and why oxygen pulls electrons towards itself in water, making the molecule polar. Caesium and francium, at the bottom of group 1, are the least electronegative.
Which elements are liquid at room temperature?
Only mercury and bromine are liquid at 25 °C and normal pressure. Caesium melts at about 28 °C and gallium at about 30 °C, so they turn liquid on a hot day or in your hand. Eleven elements are gases: hydrogen, nitrogen, oxygen, fluorine, chlorine and the six noble gases.
Where does the atomic mass come from?
It is the average mass of the element's atoms as found in nature, weighted by how common each isotope is. Chlorine is about 75 percent chlorine-35 and 25 percent chlorine-37, which gives the familiar 35.45. These standard values are published by IUPAC and are what textbooks and exam boards use.
See also: all Chemistry tools, Physics, Electronics.
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