How Many Elements Are Gaseous at Room Temperature?

Eleven elements on the periodic table exist as gases at room temperature and standard atmospheric pressure. That number is surprisingly small given that the table holds 118 confirmed elements, and it reflects how unusual it is for an element to have such weak attractions between its atoms or molecules that it refuses to condense into a liquid or solid under ordinary conditions. The identity of those eleven, and the reasons they stay airborne while everything else stays put, turn out to involve some interesting chemistry.

The Eleven Gaseous Elements

Room temperature is generally defined as roughly 20–25 °C (about 68–77 °F) at one atmosphere of pressure. Under those conditions the gaseous elements fall into a few natural groupings:

Noble gases (six): Helium, neon, argon, krypton, xenon, and radon. These elements sit in the far-right column of the periodic table and exist as lone atoms rather than molecules. Their outer electron shells are full, which makes them extraordinarily reluctant to interact with other atoms or even with each other.
Diatomic nonmetals (five): Hydrogen, nitrogen, oxygen, fluorine, and chlorine. Each of these forms a two-atom molecule in its standard state. The molecules are small and light, with weak attractions between them, so they remain gaseous under everyday conditions.

Together, those eleven account for every element that is a gas at room temperature. Every other element on the table is either a solid or, in just two cases, a liquid. Bromine and mercury are the only elements that are liquid at 25 °C, and every remaining element is a solid.

Why So Few Elements Are Gaseous

Whether an element is a gas, liquid, or solid at room temperature depends on how strongly its atoms or molecules pull on one another. The stronger those attractions, the higher the boiling point, and the more likely the element is locked into a solid or liquid phase at 25 °C. Metals, for instance, have strong metallic bonding that holds their atoms in tight lattices, which is why the vast majority of elements on the table are solid metals at room temperature. Even most nonmetals, like sulfur, phosphorus, and carbon, form large molecular or covalent-network structures with enough intermolecular or interatomic attraction to keep them solid.

The gaseous elements share a trait: their particles are small and interact weakly. Noble gases are single atoms with perfectly symmetrical electron clouds, giving them almost nothing for neighboring atoms to grab onto. The diatomic gases are small, lightweight molecules whose electrical charge is distributed either symmetrically (as in hydrogen, nitrogen, and oxygen) or in relatively compact molecules (fluorine, chlorine). The weaker the pull between particles, the lower the boiling point, and all eleven of these elements boil well below room temperature. Helium holds the record with a boiling point near absolute zero, around −269 °C, while chlorine, the warmest-boiling gas on the list, boils at about −34 °C, still far below anything you’d encounter in daily life.

Elements Near the Gas-Liquid Boundary

A handful of elements sit close enough to the dividing line that their phase at room temperature deserves a closer look. Bromine, a halogen one row below chlorine, boils at about 59 °C. That is close enough that bromine is a fuming, dark-red liquid that visibly evaporates at room temperature, but it does not quite qualify as a gas under standard conditions. Mercury, the only metallic element that is liquid at room temperature, boils far higher, at about 357 °C, but it still produces a small but hazardous amount of vapor at 25 °C. Inhaling mercury vapor is a genuine health risk: animal studies have shown that exposure causes severe respiratory acidosis, oxygen deprivation, and inflammatory damage to lung tissue even over relatively short periods.¹

On the other side of the boundary, radon is firmly a gas at room temperature, but its radioactivity means every atom you encounter is in the process of decaying. Radon’s most stable isotope has a half-life of under four days, so while it technically qualifies as a room-temperature gas, you would never collect a stable sample of it the way you would nitrogen or argon. This has made measuring its physical properties far trickier than for the other noble gases, and early estimates of its boiling point (around −62 °C) carry wider uncertainty margins than you’d expect for a simple gas.

Why the Number Is Sometimes Quoted as Twelve

You might occasionally see a count of twelve gaseous elements rather than eleven. This usually stems from including oganesson, element 118, which sits at the bottom of the noble gas column on the periodic table. Because every noble gas above it is gaseous, a first guess would be that oganesson follows the pattern. But the best available computational studies predict the opposite. Relativistic effects on oganesson’s extremely heavy electrons change the way its atoms interact with one another, and two independent theoretical approaches agree that oganesson should be a solid at ambient conditions, with a predicted melting point around 325 K (about 52 °C).² Calculations that artificially remove relativistic corrections drop that melting point to about 220 K, which would indeed make oganesson gaseous, as you’d naively expect for a noble gas.² In reality, relativity wins, and oganesson appears to be a solid. Because only a handful of oganesson atoms have ever been created, and they decay in under a millisecond, no one has directly measured its phase. The consensus among theorists, however, is that it does not belong on the gaseous list.³

The oganesson situation is a good reminder that periodic-table trends are guidelines, not laws. An element’s position suggests what its properties might be, but the physics can deliver surprises, especially at the heavy end of the table where relativistic effects grow large.

How the Noble Gases Were Found

Six of the eleven gaseous elements are noble gases, and their discovery was remarkably late. By the 1890s, chemists had catalogued most of the naturally occurring elements, yet an entire column of the periodic table was missing. Between 1894 and 1898, William Ramsay and his collaborators identified helium, neon, argon, krypton, and xenon in rapid succession, adding an entirely new group to the table.⁴ Radon was recognized a few years later as a radioactive decay product. The delay in finding these elements was not due to their scarcity. Argon makes up nearly one percent of Earth’s atmosphere, making it more abundant in air than carbon dioxide. The problem was that noble gases do not react with anything under normal conditions, so they simply passed through every chemical test of the era without leaving a trace.

The discovery of a whole group of chemically inert gases forced a rewrite of how scientists thought about atomic structure. If atoms of these elements had no tendency to form bonds, their electron configurations must represent a kind of energetic “sweet spot” that other elements strive toward. That reasoning became a foundation for understanding why atoms form bonds in the first place, and it underscored just how different the gaseous elements can be from the rest of the table.

Gaseous Elements in Everyday Life

You breathe a mixture dominated by two of the eleven gaseous elements every moment of your life. Nitrogen accounts for about 78 percent of dry air by volume, and oxygen makes up roughly 21 percent. Argon is a distant but real third at just under one percent, making it the most abundant noble gas in the atmosphere. The remaining gaseous elements are present in air at trace levels, from neon in parts per million down to radon and helium in parts per billion or less, though helium is far more concentrated in natural gas deposits.

Separating these gases from air is a massive global industry. The standard method, cryogenic distillation, cools air to extremely low temperatures until it liquefies, then exploits the different boiling points of nitrogen and oxygen to pull them apart in a double-column system.⁵ The argon, neon, krypton, and xenon that were dissolved in the liquid air can then be isolated as byproducts. Oxygen goes to hospitals, steelmaking, and water treatment. Nitrogen is used for food packaging, electronics manufacturing, and as a cryogenic coolant. Argon fills welding chambers and incandescent light bulbs. Neon lights signs. Krypton and xenon end up in specialized lighting, laser systems, and satellite thrusters.

Hydrogen and chlorine, the remaining two gaseous elements at room temperature, are mostly produced by chemical processes rather than air separation. Hydrogen is generated from natural gas or, increasingly, from water electrolysis, and feeds into ammonia production, petroleum refining, and fuel cells. Chlorine is manufactured by electrolysis of salt brine and is central to water disinfection, PVC plastic production, and pharmaceuticals. Between them, the eleven gaseous elements underpin an enormous slice of modern industry and medicine.

Elements That Become Gaseous Under Slightly Different Conditions

The eleven-element answer is strictly correct only at one atmosphere of pressure and around 20–25 °C. Change the conditions even modestly and the roster shifts. Lower the pressure, and some elements that are normally liquids or soft solids can become gases at room temperature. Raise the temperature by a modest amount, and bromine crosses its boiling point, becoming a gas above roughly 59 °C. Francium, the heaviest alkali metal, is sometimes mentioned in this context because early predictions placed its boiling point surprisingly low for a metal, though more recent estimates push it above 600 °C. In practice, francium is so radioactive and short-lived that its bulk physical properties have never been measured.

Even among the standard eleven, some are gases only by a comfortable margin. Chlorine’s boiling point of about −34 °C is far below room temperature, but it is close enough that chlorine stored at moderate pressures readily liquefies, which is how it is shipped commercially. By contrast, helium’s boiling point is so astonishingly low that liquefying it requires specialized cryogenic equipment and was not achieved until 1908, more than a decade after the other noble gases had already been liquefied.

Common Misconceptions About Gaseous Elements

Several popular confusions crop up around this topic. One is the idea that all nonmetals are gases. In fact, several nonmetals are solid at room temperature, including carbon, sulfur, phosphorus, selenium, and iodine. Iodine is particularly deceptive because it sublimes readily, producing a vivid purple vapor at room temperature, but its equilibrium state at 25 °C and one atmosphere is a shiny, crystalline solid.

Another misconception is that “noble gas” and “gaseous element” are interchangeable. The noble gases are a subset: six of the eleven. The remaining five gaseous elements are emphatically not noble; hydrogen is the most reactive element in the universe by sheer volume of chemistry it participates in, and fluorine is the most electronegative element on the table, aggressively attacking nearly every substance it contacts.

A third confusion involves water vapor. Water is not an element; it is a compound of hydrogen and oxygen. The fact that water can be gaseous does not add anything to the count of gaseous elements. The question is specifically about which of the 118 elements exist as gases in their pure elemental form at room temperature, and that number is eleven.

Helium Scarcity and Strategic Supply

Of all eleven gaseous elements, helium is the one whose supply raises the most real-world concern. Unlike nitrogen, oxygen, and argon, which can be pulled from the atmosphere in unlimited quantities, helium is extracted from underground natural gas reservoirs where it has accumulated over billions of years through radioactive decay of heavy elements in Earth’s crust. Once released into the atmosphere, helium is so light that it gradually escapes to space, making it effectively non-renewable on any human timescale.

This matters because helium has critical applications that no other element can fill. Liquid helium cools the superconducting magnets in MRI machines and particle accelerators, reaching temperatures below 4 K, far colder than liquid nitrogen can achieve. Helium is also used as a protective atmosphere in semiconductor manufacturing, a carrier gas in analytical chemistry, and a pressurizing agent in rocket fuel systems. Periodic helium shortages over the past two decades have driven prices up and forced hospitals and research labs to ration their supply. The U.S. Federal Helium Reserve, once the world’s dominant stockpile, has been winding down, shifting more of the supply burden to private extraction operations in Qatar, Algeria, and Russia. For a gas that most people associate with party balloons, the stakes of a helium shortage are surprisingly high.