Chemistry Tool · All 118 elements
Interactive Periodic Table
Groups · Periods · Electron shells · Compare any two
Explore atomic number, mass, electron configuration, electronegativity and more — search, filter, compare, all in your browser.
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The periodic table below is laid out in the standard form, with groups 1 to 18 running left to right and periods 1 to 7 running top to bottom. Each element is a button: press Enter or Space to open its full properties, use the arrow keys to move between elements, and press Escape to close the details panel.
Quick tips — tap, search & swipe
- Tap any element tile to open its full properties
- Search by name, symbol (e.g. Au) or atomic number (e.g. 79)
- Swipe the table horizontally on phone — layout stays scientifically correct
- Filter with the chips below — try Metals, Gases or ☢ Radioactive
Category
What this interactive periodic table shows
This interactive periodic table includes all 118 chemical elements and lets users explore atomic number, atomic mass, symbol, category, group, period, electron configuration, electronegativity and other properties. Every element is a clickable tile in the conventional long-form layout, so the position of an element on the screen carries the same information it does on a wall chart: its group tells you how it bonds, its period tells you which electron shell is filling, and its colour tells you which family it belongs to.
- 118confirmed elements, hydrogen to oganesson
- 18groups, the vertical columns
- 7periods, the horizontal rows
- 38elements with no stable isotope
- 11elements that are gases at 25 °C
- 2elements that are liquid at 25 °C
Values are shown only where a published value exists. Where a property has never been measured — the melting point of an element that has only ever existed as a few dozen atoms, for example — the tool prints N/A rather than filling the gap with a guess.
What is the periodic table?
The periodic table arranges every chemical element in order of increasing atomic number, in rows and columns chosen so that elements with similar chemical behaviour line up underneath one another.
Dmitri Mendeleev published the first widely accepted version in 1869. What made it more than a list was that he left gaps where no known element fitted the pattern, and predicted the properties of the elements that would fill them. Gallium, scandium and germanium were found soon after and matched his predictions closely. The modern table is ordered by proton count rather than atomic weight, but the logic is unchanged: chemistry repeats periodically as electron shells fill.
How the periodic table is organised
Reading left to right along a row, each element has one more proton and one more electron than the last. When a shell finishes filling, the next element starts a new row directly beneath the element it resembles. That single rule produces the whole shape of the table, including its awkward-looking blocks:
- Groups (1–18) are the columns. Members of a group share an outer-shell electron count and therefore react alike.
- Periods (1–7) are the rows. Members of a period share the outermost shell that is being filled.
- Blocks (s, p, d, f) name the type of subshell being filled, which is why the table divides visually into a tall left section, a wide right section, a central transition metal block and the two rows underneath.
Groups and periods
Group number is the strongest single clue to an element's chemistry. Group 1 metals each have one loosely held outer electron and react vigorously with water; group 17 elements are each one electron short of a full shell and are aggressive oxidisers; group 18 elements have full shells and barely react at all. Sodium and potassium behave alike because they sit in the same column, not because they have similar masses.
Moving across a period, atoms get smaller and hold their electrons more tightly, so metallic character falls and electronegativity rises. Moving down a group, atoms gain shells and get larger, so the outer electrons are further from the nucleus and easier to lose — which is why caesium is more reactive than lithium, and fluorine more reactive than iodine.
Element categories
Metals vs nonmetals
Metals conduct heat and electricity, are malleable and tend to lose electrons; nonmetals are poor conductors, are brittle as solids and tend to gain or share electrons. Metals occupy most of the table, and the boundary between the two runs as a staircase down the right-hand side.
Use the Metals and Nonmetals quick filters to highlight each set. Sitting on the staircase itself are the six metalloids — boron, silicon, germanium, arsenic, antimony and tellurium — which behave as either depending on the circumstances, and whose intermediate conductivity is what makes semiconductor electronics possible.
What are noble gases?
The noble gases are the six group 18 elements — helium, neon, argon, krypton, xenon and radon. Their outer shells are full, which makes them almost completely unreactive.
"Almost" matters. Xenon compounds have been made since 1962 and krypton difluoride is real, so the older label "inert gases" was retired. Helium and neon, however, form no ordinary compounds at all. Radon is radioactive and is the only one flagged as such in this table.
What are halogens?
The halogens are the group 17 elements — fluorine, chlorine, bromine, iodine and astatine — highly reactive nonmetals that readily form -1 ions and salts.
The group is a neat demonstration of trends: reactivity and electronegativity both fall going down it, and it covers three states of matter at room temperature, from gaseous fluorine and chlorine through liquid bromine to solid iodine. Astatine is so rare and so short-lived that its bulk properties have never been observed, which is why its state is listed as unknown here rather than guessed at.
What are transition metals?
Transition metals are the elements of groups 3 to 12, in which d-orbitals fill. They are typically hard, dense and high-melting, show several oxidation states and form coloured compounds.
This is where most familiar metals live: iron, copper, nickel, chromium, zinc, silver, gold and platinum. Partly filled d-orbitals give them their two signature traits — variable valency, which is why iron forms both Fe²⁺ and Fe³⁺, and the ability to bind and activate other molecules, which makes them the backbone of industrial catalysis.
What are lanthanides?
The lanthanides are the fifteen elements from lanthanum (57) to lutetium (71), in which the 4f subshell fills. They are the bulk of what industry calls the rare earth elements.
Their chemistry is remarkably uniform — nearly all of them form +3 ions of very similar size — which makes them hard to separate from one another and is the reason rare earth refining is difficult rather than geologically scarce. They are indispensable to permanent magnets, laser crystals, display phosphors and MRI contrast agents.
What are actinides?
The actinides are the fifteen elements from actinium (89) to lawrencium (103), in which the 5f subshell fills. Every one of them is radioactive.
Only thorium and uranium are found in any quantity in nature. The rest are made in reactors or accelerators, and the heaviest of them — fermium onward — have never been produced in weighable amounts, so their bulk properties are listed as unknown here.
Atomic number and atomic mass
What is atomic number?
The atomic number is the number of protons in an atom's nucleus. It defines the element and is the value the periodic table is ordered by.
Change the proton count and you have a different element; change the neutron count and you have a different isotope of the same one. In a neutral atom the atomic number also equals the electron count, which is why it controls chemical behaviour so completely.
What is atomic mass?
Atomic mass is the mass of an atom in unified atomic mass units (u). The value on a periodic table is normally the standard atomic weight — the average across the element's naturally occurring isotopes, weighted by abundance.
That averaging is why chlorine reads 35.45 rather than a whole number: natural chlorine is roughly three parts chlorine-35 to one part chlorine-37. For elements with no stable isotope there is no meaningful average, so this table shows the mass number of the most stable isotope in square brackets instead — for example [98] for technetium. Values are given to the precision published in abridged standard atomic weight tables rather than rounded further.
What is electronegativity?
Electronegativity measures how strongly an atom pulls on the electrons it shares in a bond. This tool uses the Pauling scale, on which fluorine is the highest at 3.98.
Its practical use is predicting bond type. Two atoms with nearly equal values share electrons roughly evenly and form a covalent bond; a large difference means one atom takes the electrons outright and an ionic bond results. Electronegativity increases up a group and across a period, so the highest values cluster in the top-right corner and the lowest at the bottom-left.
Noble gases and several synthetic elements have no accepted Pauling value. Those are shown as N/A — no number has been invented to fill the cell.
What is electron configuration?
Electron configuration describes how an atom's electrons are arranged across shells and subshells. Carbon is 1s² 2s² 2p²; in noble gas notation the same configuration is written [He] 2s² 2p².
Each detail panel shows both forms. The full configuration lists every electron from the innermost shell outward; the noble gas notation replaces the filled inner shells with the preceding noble gas in brackets, which is far easier to read for heavy elements — uranium is [Rn] 5f³ 6d¹ 7s² rather than a string of nineteen terms.
A handful of elements break the expected filling order because a half-filled or filled subshell is more stable. Chromium is [Ar] 3d⁵ 4s¹ rather than 3d⁴ 4s², and copper is [Ar] 3d¹⁰ 4s¹ rather than 3d⁹ 4s². Those anomalies are recorded in the dataset rather than smoothed over. Configurations for elements above atomic number 103 are theoretical predictions, since there is no way to measure them.
States of matter and radioactive elements
Which elements are gases at room temperature?
Eleven: hydrogen, helium, nitrogen, oxygen, fluorine, neon, chlorine, argon, krypton, xenon and radon. Only two elements are liquid — bromine and mercury. Everything else with a measured state is a solid.
States in this tool are given at 25 °C (298.15 K) and 100 kPa. That reference point matters at the margins: caesium melts at 28.5 °C and gallium at 29.8 °C, so both are solids by this convention even though either will melt in a warm hand. Twenty elements are listed as unknown — astatine and everything from fermium onward — because no bulk sample has ever existed to observe.
Which elements are radioactive?
Thirty-eight elements have no stable isotope: technetium (43), promethium (61) and every element from bismuth (83) upward. Those are the elements this tool flags as radioactive.
This is a definition of the element, not of a particular sample. Potassium, carbon and hydrogen all have radioactive isotopes — potassium-40, carbon-14 and tritium — but each also has stable isotopes that dominate in nature, so they are not flagged. Bismuth is included because its only primordial isotope, bismuth-209, was shown in 2003 to decay, albeit with a half-life around a billion times the age of the universe; for every practical purpose it behaves as a stable, non-toxic metal.
Use the ☢ Radioactive filter to highlight all 38, or switch Colour by to Radioactivity to shade the whole table along that line.
What does the periodic table tell you?
Read properly, a single tile answers a lot of questions at once. From an element's position you can predict:
- How it bonds — group number gives the outer electron count and the ions it will form.
- How reactive it is — metallic reactivity increases down a group, nonmetallic reactivity increases up one.
- How big its atoms are — radius grows down a group and shrinks across a period.
- How tightly it holds electrons — ionisation energy and electronegativity both rise up and to the right.
- Which elements it resembles — its vertical neighbours, almost always more closely than its horizontal ones.
That predictive power is what makes the table worth memorising the shape of, rather than the numbers in it.
Periodic table of elements: full list
Every element in one sortable-by-eye list, with the properties most often needed for homework and revision. The table follows the filters above, so highlighting the noble gases in the interactive table narrows this list to the same six elements. It scrolls sideways on small screens.
118 of 118 elements shown
| Atomic number | Symbol | Element | Atomic mass (u) | Category | State | Electronegativity | Radioactive |
|---|---|---|---|---|---|---|---|
| 1 | H | Hydrogen | 1.008 | Nonmetal | Gas | 2.2 | No |
| 2 | He | Helium | 4.0026 | Noble Gas | Gas | N/A | No |
| 3 | Li | Lithium | 6.94 | Alkali Metal | Solid | 0.98 | No |
| 4 | Be | Beryllium | 9.0122 | Alkaline Earth Metal | Solid | 1.57 | No |
| 5 | B | Boron | 10.81 | Metalloid | Solid | 2.04 | No |
| 6 | C | Carbon | 12.011 | Nonmetal | Solid | 2.55 | No |
| 7 | N | Nitrogen | 14.007 | Nonmetal | Gas | 3.04 | No |
| 8 | O | Oxygen | 15.999 | Nonmetal | Gas | 3.44 | No |
| 9 | F | Fluorine | 18.998 | Halogen | Gas | 3.98 | No |
| 10 | Ne | Neon | 20.180 | Noble Gas | Gas | N/A | No |
| 11 | Na | Sodium | 22.990 | Alkali Metal | Solid | 0.93 | No |
| 12 | Mg | Magnesium | 24.305 | Alkaline Earth Metal | Solid | 1.31 | No |
| 13 | Al | Aluminium | 26.982 | Post-transition Metal | Solid | 1.61 | No |
| 14 | Si | Silicon | 28.085 | Metalloid | Solid | 1.9 | No |
| 15 | P | Phosphorus | 30.974 | Nonmetal | Solid | 2.19 | No |
| 16 | S | Sulfur | 32.06 | Nonmetal | Solid | 2.58 | No |
| 17 | Cl | Chlorine | 35.45 | Halogen | Gas | 3.16 | No |
| 18 | Ar | Argon | 39.95 | Noble Gas | Gas | N/A | No |
| 19 | K | Potassium | 39.098 | Alkali Metal | Solid | 0.82 | No |
| 20 | Ca | Calcium | 40.078 | Alkaline Earth Metal | Solid | 1 | No |
| 21 | Sc | Scandium | 44.956 | Transition Metal | Solid | 1.36 | No |
| 22 | Ti | Titanium | 47.867 | Transition Metal | Solid | 1.54 | No |
| 23 | V | Vanadium | 50.942 | Transition Metal | Solid | 1.63 | No |
| 24 | Cr | Chromium | 51.996 | Transition Metal | Solid | 1.66 | No |
| 25 | Mn | Manganese | 54.938 | Transition Metal | Solid | 1.55 | No |
| 26 | Fe | Iron | 55.845 | Transition Metal | Solid | 1.83 | No |
| 27 | Co | Cobalt | 58.933 | Transition Metal | Solid | 1.88 | No |
| 28 | Ni | Nickel | 58.693 | Transition Metal | Solid | 1.91 | No |
| 29 | Cu | Copper | 63.546 | Transition Metal | Solid | 1.9 | No |
| 30 | Zn | Zinc | 65.38 | Transition Metal | Solid | 1.65 | No |
| 31 | Ga | Gallium | 69.723 | Post-transition Metal | Solid | 1.81 | No |
| 32 | Ge | Germanium | 72.630 | Metalloid | Solid | 2.01 | No |
| 33 | As | Arsenic | 74.922 | Metalloid | Solid | 2.18 | No |
| 34 | Se | Selenium | 78.971 | Nonmetal | Solid | 2.55 | No |
| 35 | Br | Bromine | 79.904 | Halogen | Liquid | 2.96 | No |
| 36 | Kr | Krypton | 83.798 | Noble Gas | Gas | 3 | No |
| 37 | Rb | Rubidium | 85.468 | Alkali Metal | Solid | 0.82 | No |
| 38 | Sr | Strontium | 87.62 | Alkaline Earth Metal | Solid | 0.95 | No |
| 39 | Y | Yttrium | 88.906 | Transition Metal | Solid | 1.22 | No |
| 40 | Zr | Zirconium | 91.224 | Transition Metal | Solid | 1.33 | No |
| 41 | Nb | Niobium | 92.906 | Transition Metal | Solid | 1.6 | No |
| 42 | Mo | Molybdenum | 95.95 | Transition Metal | Solid | 2.16 | No |
| 43 | Tc | Technetium | [98] | Transition Metal | Solid | 1.9 | Yes |
| 44 | Ru | Ruthenium | 101.07 | Transition Metal | Solid | 2.2 | No |
| 45 | Rh | Rhodium | 102.91 | Transition Metal | Solid | 2.28 | No |
| 46 | Pd | Palladium | 106.42 | Transition Metal | Solid | 2.2 | No |
| 47 | Ag | Silver | 107.87 | Transition Metal | Solid | 1.93 | No |
| 48 | Cd | Cadmium | 112.41 | Transition Metal | Solid | 1.69 | No |
| 49 | In | Indium | 114.82 | Post-transition Metal | Solid | 1.78 | No |
| 50 | Sn | Tin | 118.71 | Post-transition Metal | Solid | 1.96 | No |
| 51 | Sb | Antimony | 121.76 | Metalloid | Solid | 2.05 | No |
| 52 | Te | Tellurium | 127.60 | Metalloid | Solid | 2.1 | No |
| 53 | I | Iodine | 126.90 | Halogen | Solid | 2.66 | No |
| 54 | Xe | Xenon | 131.29 | Noble Gas | Gas | 2.6 | No |
| 55 | Cs | Caesium | 132.91 | Alkali Metal | Solid | 0.79 | No |
| 56 | Ba | Barium | 137.33 | Alkaline Earth Metal | Solid | 0.89 | No |
| 57 | La | Lanthanum | 138.91 | Lanthanide | Solid | 1.1 | No |
| 58 | Ce | Cerium | 140.12 | Lanthanide | Solid | 1.12 | No |
| 59 | Pr | Praseodymium | 140.91 | Lanthanide | Solid | 1.13 | No |
| 60 | Nd | Neodymium | 144.24 | Lanthanide | Solid | 1.14 | No |
| 61 | Pm | Promethium | [145] | Lanthanide | Solid | N/A | Yes |
| 62 | Sm | Samarium | 150.36 | Lanthanide | Solid | 1.17 | No |
| 63 | Eu | Europium | 151.96 | Lanthanide | Solid | 1.2 | No |
| 64 | Gd | Gadolinium | 157.25 | Lanthanide | Solid | 1.2 | No |
| 65 | Tb | Terbium | 158.93 | Lanthanide | Solid | 1.1 | No |
| 66 | Dy | Dysprosium | 162.50 | Lanthanide | Solid | 1.22 | No |
| 67 | Ho | Holmium | 164.93 | Lanthanide | Solid | 1.23 | No |
| 68 | Er | Erbium | 167.26 | Lanthanide | Solid | 1.24 | No |
| 69 | Tm | Thulium | 168.93 | Lanthanide | Solid | 1.25 | No |
| 70 | Yb | Ytterbium | 173.05 | Lanthanide | Solid | 1.1 | No |
| 71 | Lu | Lutetium | 174.97 | Lanthanide | Solid | 1.27 | No |
| 72 | Hf | Hafnium | 178.49 | Transition Metal | Solid | 1.3 | No |
| 73 | Ta | Tantalum | 180.95 | Transition Metal | Solid | 1.5 | No |
| 74 | W | Tungsten | 183.84 | Transition Metal | Solid | 2.36 | No |
| 75 | Re | Rhenium | 186.21 | Transition Metal | Solid | 1.9 | No |
| 76 | Os | Osmium | 190.23 | Transition Metal | Solid | 2.2 | No |
| 77 | Ir | Iridium | 192.22 | Transition Metal | Solid | 2.2 | No |
| 78 | Pt | Platinum | 195.08 | Transition Metal | Solid | 2.28 | No |
| 79 | Au | Gold | 196.97 | Transition Metal | Solid | 2.54 | No |
| 80 | Hg | Mercury | 200.59 | Transition Metal | Liquid | 2 | No |
| 81 | Tl | Thallium | 204.38 | Post-transition Metal | Solid | 1.62 | No |
| 82 | Pb | Lead | 207.2 | Post-transition Metal | Solid | 2.33 | No |
| 83 | Bi | Bismuth | 208.98 | Post-transition Metal | Solid | 2.02 | Yes |
| 84 | Po | Polonium | [209] | Post-transition Metal | Solid | 2 | Yes |
| 85 | At | Astatine | [210] | Halogen | Unknown | 2.2 | Yes |
| 86 | Rn | Radon | [222] | Noble Gas | Gas | N/A | Yes |
| 87 | Fr | Francium | [223] | Alkali Metal | Solid | 0.7 | Yes |
| 88 | Ra | Radium | [226] | Alkaline Earth Metal | Solid | 0.9 | Yes |
| 89 | Ac | Actinium | [227] | Actinide | Solid | 1.1 | Yes |
| 90 | Th | Thorium | 232.04 | Actinide | Solid | 1.3 | Yes |
| 91 | Pa | Protactinium | 231.04 | Actinide | Solid | 1.5 | Yes |
| 92 | U | Uranium | 238.03 | Actinide | Solid | 1.38 | Yes |
| 93 | Np | Neptunium | [237] | Actinide | Solid | 1.36 | Yes |
| 94 | Pu | Plutonium | [244] | Actinide | Solid | 1.28 | Yes |
| 95 | Am | Americium | [243] | Actinide | Solid | 1.13 | Yes |
| 96 | Cm | Curium | [247] | Actinide | Solid | 1.28 | Yes |
| 97 | Bk | Berkelium | [247] | Actinide | Solid | 1.3 | Yes |
| 98 | Cf | Californium | [251] | Actinide | Solid | 1.3 | Yes |
| 99 | Es | Einsteinium | [252] | Actinide | Solid | 1.3 | Yes |
| 100 | Fm | Fermium | [257] | Actinide | Unknown | 1.3 | Yes |
| 101 | Md | Mendelevium | [258] | Actinide | Unknown | 1.3 | Yes |
| 102 | No | Nobelium | [259] | Actinide | Unknown | 1.3 | Yes |
| 103 | Lr | Lawrencium | [266] | Actinide | Unknown | 1.3 | Yes |
| 104 | Rf | Rutherfordium | [267] | Transition Metal | Unknown | N/A | Yes |
| 105 | Db | Dubnium | [268] | Transition Metal | Unknown | N/A | Yes |
| 106 | Sg | Seaborgium | [269] | Transition Metal | Unknown | N/A | Yes |
| 107 | Bh | Bohrium | [270] | Transition Metal | Unknown | N/A | Yes |
| 108 | Hs | Hassium | [269] | Transition Metal | Unknown | N/A | Yes |
| 109 | Mt | Meitnerium | [278] | Unknown Properties | Unknown | N/A | Yes |
| 110 | Ds | Darmstadtium | [281] | Unknown Properties | Unknown | N/A | Yes |
| 111 | Rg | Roentgenium | [282] | Unknown Properties | Unknown | N/A | Yes |
| 112 | Cn | Copernicium | [285] | Unknown Properties | Unknown | N/A | Yes |
| 113 | Nh | Nihonium | [286] | Unknown Properties | Unknown | N/A | Yes |
| 114 | Fl | Flerovium | [289] | Unknown Properties | Unknown | N/A | Yes |
| 115 | Mc | Moscovium | [290] | Unknown Properties | Unknown | N/A | Yes |
| 116 | Lv | Livermorium | [293] | Unknown Properties | Unknown | N/A | Yes |
| 117 | Ts | Tennessine | [294] | Unknown Properties | Unknown | N/A | Yes |
| 118 | Og | Oganesson | [294] | Unknown Properties | Unknown | N/A | Yes |
Frequently asked questions
What is the periodic table?
The periodic table is an arrangement of all the chemical elements in order of increasing atomic number, laid out so that elements with similar chemical behaviour fall into the same vertical column. It was published in recognisable form by Dmitri Mendeleev in 1869 and is the single most useful summary of chemistry ever produced, because an element's position tells you a great deal about how it will react.
How many elements are in the periodic table?
There are 118 confirmed elements, from hydrogen (atomic number 1) to oganesson (atomic number 118). All 118 are included in this interactive table. Elements up to uranium (92) occur naturally, apart from technetium and promethium, which are found only in traces; everything above uranium is made in reactors or particle accelerators.
What is an atomic number?
The atomic number is the number of protons in an atom's nucleus. It defines which element the atom is: every atom with six protons is carbon, and nothing with a different proton count can be. In a neutral atom it also equals the number of electrons, which is why it governs chemical behaviour. Atomic number is the value the periodic table is ordered by.
What is atomic mass?
Atomic mass is the mass of an atom, measured in unified atomic mass units (u), where one unit is one twelfth the mass of a carbon-12 atom. The value shown on a periodic table is normally the standard atomic weight: the average mass of the element's isotopes weighted by how common they are on Earth. That is why chlorine reads 35.45 rather than a whole number.
Why are some atomic masses shown in square brackets?
Square brackets mean the element has no stable isotope, so no meaningful natural average exists. Instead the number given is the mass number of its most stable or best-characterised isotope. In this table technetium appears as [98] and oganesson as [294] for exactly that reason.
What is an element symbol?
An element symbol is the one- or two-letter abbreviation used to write an element in formulae and equations, such as H for hydrogen, Ca for calcium and Au for gold. The first letter is always capitalised and the second, if there is one, is always lower case. Several symbols come from Latin names, which is why gold is Au from aurum and lead is Pb from plumbum.
What are groups in the periodic table?
Groups are the eighteen vertical columns. Elements in the same group have the same number of electrons in their outermost shell, which is why they react in similar ways: group 1 metals all form +1 ions, group 17 elements all form -1 ions, and group 18 elements are all but unreactive. Group number is the strongest single predictor of an element's chemistry.
What are periods in the periodic table?
Periods are the seven horizontal rows. All the elements in a period have their outermost electrons in the same shell, and moving left to right across a period that shell fills one electron at a time. Atoms therefore get smaller and more electronegative across a period, and larger going down a group.
What are metals?
Metals are elements that conduct heat and electricity well, are usually shiny, malleable and ductile, and tend to lose electrons to form positive ions. They occupy most of the table — the alkali metals, alkaline earth metals, transition metals, post-transition metals, lanthanides and actinides. In this dataset 84 of the 118 elements are classified as metals; the ten superheavy elements whose properties have never been measured are left unclassified.
What are nonmetals?
Nonmetals are poor conductors, are brittle rather than malleable as solids, and tend to gain or share electrons. They sit on the upper right of the table and include hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur and selenium, plus the halogens and the noble gases. There are far fewer of them than metals, but they make up most of the mass of living things.
What are metalloids?
Metalloids sit along the staircase between metals and nonmetals and share properties with both — typically the appearance of a metal but the brittleness and poor conductivity of a nonmetal. The six treated as metalloids here are boron, silicon, germanium, arsenic, antimony and tellurium. Their intermediate conductivity is exactly what makes semiconductors possible.
What are noble gases?
The noble gases are the six elements in group 18: helium, neon, argon, krypton, xenon and radon. Their outer electron shells are full, so they have almost no tendency to gain, lose or share electrons and are chemically very unreactive. Xenon and krypton do form real compounds under forcing conditions, so "inert" is not quite accurate. Radon is radioactive.
What are halogens?
The halogens are the group 17 elements: fluorine, chlorine, bromine, iodine and astatine. Each is one electron short of a full shell, which makes them highly reactive nonmetals that readily form -1 ions and salts. Reactivity falls down the group, and the group spans all three states at room temperature — fluorine and chlorine are gases, bromine is a liquid and iodine is a solid.
What are transition metals?
Transition metals are the elements in groups 3 to 12, in which d-orbitals are being filled. They are hard, dense, high-melting metals that typically show several oxidation states, form coloured compounds and make good catalysts. Iron, copper, nickel, chromium, silver, gold and platinum are all transition metals.
What are lanthanides?
The lanthanides are the fifteen elements from lanthanum (57) to lutetium (71), in which the 4f subshell fills. They are reactive silvery metals with very similar chemistry, which makes them difficult to separate from one another. Together with scandium and yttrium they are known as the rare earth elements, and they are essential to strong magnets, lasers and phosphors.
What are actinides?
The actinides are the fifteen elements from actinium (89) to lawrencium (103), in which the 5f subshell fills. Every one of them is radioactive. Only thorium and uranium occur in useful quantities in nature; the rest are made artificially, and the heaviest exist only as a handful of short-lived atoms.
Which elements are radioactive?
An element is counted as radioactive here when it has no stable isotope. That applies to technetium (43), promethium (61) and every element from bismuth (83) upward — 38 elements in total. Bismuth is included because its only primordial isotope does decay, although with a half-life a billion times the age of the universe. Many other elements, such as potassium and carbon, have radioactive isotopes alongside stable ones and are not flagged.
What is electron configuration?
Electron configuration describes how an atom's electrons are distributed across its shells and subshells, written as a series of orbital labels with the electron count as a superscript. Carbon is 1s² 2s² 2p². It matters because the outermost electrons determine bonding: two elements with analogous outer configurations behave alike, which is what puts them in the same group.
What is noble gas notation?
Noble gas notation is a shorthand that replaces the inner electrons with the symbol of the preceding noble gas in square brackets. Instead of writing carbon as 1s² 2s² 2p² you write [He] 2s² 2p², and instead of writing out all 92 electrons of uranium you write [Rn] 5f³ 6d¹ 7s². This tool shows both forms for every element.
What is electronegativity?
Electronegativity measures how strongly an atom attracts the shared electrons in a bond. The usual scale is Pauling's, on which fluorine is highest at 3.98 and caesium lowest among common elements at 0.79. The difference between two atoms' values predicts the bond: a large difference gives an ionic bond, a small one a covalent bond. Noble gases and several synthetic elements have no accepted value and are shown as N/A.
Which element has the highest electronegativity?
Fluorine, at 3.98 on the Pauling scale. Electronegativity rises going up a group and across a period, so fluorine sits at the extreme. Oxygen is second at 3.44 and chlorine and nitrogen follow. Francium and caesium are at the other end of the scale.
Which element has atomic number 1?
Hydrogen. It has a single proton and, in its ordinary form, a single electron and no neutrons, making it the lightest and simplest of all elements. It is also the most abundant element in the universe by a wide margin.
What is the difference between atomic mass and atomic number?
Atomic number counts protons only and is always a whole number; it identifies the element. Atomic mass measures the mass of the atom in unified mass units and reflects protons plus neutrons, averaged over the element's isotopes, so it is usually not a whole number. Carbon has atomic number 6 and atomic mass 12.011.
What elements are gases at room temperature?
Eleven elements are gases at 25 °C and standard pressure: hydrogen, helium, nitrogen, oxygen, fluorine, neon, chlorine, argon, krypton, xenon and radon. Use the Gases quick filter to highlight them in the table.
Which elements are liquid at room temperature?
Only two: bromine and mercury. Caesium, gallium, rubidium and francium all melt just above room temperature — gallium at about 30 °C — so they are solids at 25 °C but will liquefy in a warm hand.
What are s-block, p-block, d-block and f-block elements?
The blocks name the subshell that is being filled. The s-block is groups 1 and 2 plus helium; the p-block is groups 13 to 18; the d-block is the transition metals in groups 3 to 12; and the f-block is the lanthanides and actinides shown in the two separate rows. Switching the Colour by control to Block shades the table this way.
How do I find an element by atomic number or symbol?
Type into the search box. A number such as 8 finds oxygen, a symbol such as Au finds gold, and a name such as helium finds helium. The best match is outlined and scrolled into view inside the table, and pressing Enter opens its full details.
Can I compare two elements?
Yes. Open Compare in the toolbar, or press Compare inside any element's detail panel to preload it, then choose a second element. The comparison shows atomic number, mass, category, group, period, block, state, electronegativity, atomic radius, ionisation energy, electron affinity, melting and boiling points, density, electron configuration, oxidation states and radioactivity side by side.
Can I filter radioactive elements?
Yes. The ☢ Radioactive quick filter highlights all 38 elements with no stable isotope and dims the rest, and the element count updates to match. You can combine it with other filters — Radioactive plus Metals, for example — and the Colour by control has a Radioactivity mode that shades the whole table by it.
Why are the lanthanides and actinides shown in separate rows?
Because printing them in place would make the table fifteen columns wider and awkward to read. They belong in period 6 and period 7 immediately after the group 2 elements, which is why the markers 57–71 and 89–103 appear there. Pulling the f-block out into two rows underneath is the standard convention and keeps the main table compact.
Is this periodic table mobile friendly?
Yes. On a phone the table keeps its correct scientific layout and scrolls horizontally inside its own container, so the page itself never scrolls sideways. Tapping an element opens a full detail sheet from the bottom of the screen, and the filters and search stay reachable above the table.
Do I need to install anything or sign up?
No. The whole tool is a single static page: the element data ships with it and every search, filter and comparison runs in your browser. There is no sign-up, no account and no network request once the page has loaded, so it keeps working offline in an already-open tab.
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