40 Fun Facts About Rubidium

Rubidium was named by its discoverers for which color of the bright lines in the light it emits?

Red is the answer: the name comes from rubidus, meaning deep red, after bright lines in its spectrum that matched no known element.

Rubidium metal melts at about 39 °C, only a couple of degrees warmer than which of these?

The human body runs at about 37 °C, which makes rubidium one of only five metals that are liquid at or near room temperature, alongside mercury and gallium.

Which element sits immediately before rubidium, element number 37, in the periodic table?

Krypton shares its name with Superman's home planet, and radioactive rubidium-82 decays into it within minutes.

Rubidium sounds rare, yet it is more abundant in Earth's crust than which of these everyday metals?

Copper is scarcer in the crust than rubidium, which only seems rare because it never gathers into rich ores of its own.

Doctors inject short-lived radioactive rubidium-82 to picture how well blood is reaching which organ?

The heart muscle soaks up rubidium-82 in step with its blood supply, and with a half-life of barely over a minute the tracer must be made beside the patient.

Radioactive rubidium-87 has a half-life more than three times the 13.8-billion-year age of what?

The universe is about 13.8 billion years old, while rubidium-87 needs roughly 49 billion years to half decay, which is why about 28% of natural rubidium is still radioactive.

Which German chemist co-discovered rubidium by studying the colors that chemicals give to a flame?

Robert Bunsen spotted rubidium in the light of a flame; his dangerous earlier work on arsenic compounds had cost him the sight in his right eye.

Rubidium reacts so violently with water that the reaction can ignite which gas it releases?

Hydrogen is released so fast that shock waves form in the water, and rubidium, denser than its lighter relatives, sinks as it reacts.

NASA's Cold Atom Laboratory has chilled rubidium atoms into an ultracold cloud while orbiting aboard what?

A space station is the ideal home: in the endless free fall of the International Space Station, the rubidium cloud could be watched for more than a second.

A natural vibration in rubidium, about 6.8 billion cycles a second, regulates which devices aboard GPS satellites?

Atomic clocks based on rubidium are the cheapest, smallest and most widely made kind, keeping time for navigation signals far above the Earth.

Living cells absorb rubidium ions because they mistake them for which essential nutrient element?

Potassium and rubidium ions carry the same charge and behave alike, so cells pull both in, although rubidium is not known to be a nutrient for any living thing.

Biology labs treat living cells with rubidium chloride to make them take up which molecule?

DNA slips in after the salt treatment makes the cells swell, the best-known job of rubidium chloride, probably the most used rubidium compound.

Rubidium nitrate is sometimes added to fireworks to give the bursts which color?

Purple, or a pale mauve, is what rubidium salts show in a laboratory flame test, the same trick that fireworks makers borrow.

Which two-letter symbol stands for rubidium, element number 37, on the periodic table?

Rb is rubidium; the lookalike symbols Ru, Rh and Ra belong to ruthenium, rhodium and radium.

Rubidium belongs to which family of soft, highly reactive elements found in group 1 of the periodic table?

Alkali metals each have a single outer electron that they give up easily, which is why rubidium is never found as a pure metal in nature.

To keep it safe and pure, rubidium metal is usually stored submerged in which dry liquid?

Mineral oil keeps moisture away, and the alternative is a sealed ampoule of inert gas; even so, traces of air seeping into the oil slowly form peroxides.

Cooling rubidium atoms into a new state of matter in 1995 earned Eric Cornell and Carl Wieman which honor?

Nobel Prize in Physics went to both men in 2001, shared with Wolfgang Ketterle, who made the same state of matter later that year using sodium.

Rubidium is so reactive that a fresh piece exposed to open air has been reported to do what?

Catch fire is right: rubidium can ignite spontaneously in air, a trait chemists call pyrophoric, so samples are handled only under inert gas.

Which German physicist, known for his laws of electrical circuits, co-discovered rubidium with a chemist colleague?

Gustav Kirchhoff also read the Sun's light the same way, showing in 1859 that it contains sodium, two years before rubidium turned up.

Rubidium was first identified in a laboratory in which German city, home to the country's oldest university?

Heidelberg drew both discoverers to its university in the 1850s; founded in 1386, it is the oldest in Germany.

Rubidium was first detected in which lilac-colored mica, of which its discoverers processed 150 kg?

Lepidolite owes its pink tints to traces of manganese, and it is still mined today as a source of rubidium.

Rubidium was the second element discovered by its spectral lines, shortly after which other soft metal?

Caesium came first, in 1860, when the same two scientists evaporated 44,000 litres of mineral water to collect a few grams of its salts.

When an atom of radioactive rubidium-87 decays, it becomes a stable atom of which neighboring element?

Strontium is the next element along: each decay turns a neutron into a proton, nudging rubidium one place up the periodic table.

In 1995, physicists chilled a cloud of rubidium-87 atoms to near absolute zero and created the first what?

A Bose–Einstein condensate makes separate atoms behave as one; predicted in the 1920s, this first one held only about two thousand of them.

Eric Cornell and Carl Wieman made rubidium atoms behave as one super-atom in a laboratory in which Colorado city?

Boulder hosts JILA, the joint university and government institute where the pair cooled their rubidium to 170 billionths of a degree above absolute zero.

Rubidium chloride has been tested on volunteers as a possible treatment for which condition?

Depression was the target: volunteers took up to 720 mg a day for 60 days, but rubidium chloride never became a standard treatment.

Rubidium silver iodide, the best ion-conducting crystal known at room temperature, has been used in which devices?

Batteries can use it as a solid electrolyte: silver ions slip through the crystal's framework so freely that no liquid is needed.

Scientists measure the slow decay of rubidium-87, which takes billions of years, to find the age of what?

Rocks from Earth, the Moon and meteorites have all been dated this way, by weighing how much rubidium-87 has turned into its decay product.

Rubidium carbonate is added to which material to toughen it for fiber optics and night-vision devices?

Glass gains stability and durability from the additive while conducting less electricity, one of the few industrial jobs rubidium has.

Cheap, compact rubidium oscillators keep signals precisely timed inside which everyday network equipment?

Mobile phone towers rely on them to hold their radio frequencies steady, and television transmitters use the same rubidium references.

Rubidium-87 became a favorite of cold-atom labs partly because it responds to cheap lasers made for which devices?

CD writers use inexpensive diode lasers that happen to work at the right wavelength for rubidium, which made it the most popular atom for ultracold experiments.

Arrays of single rubidium atoms, trapped and steered with lasers, are the building blocks of which machines?

Quantum computers of the neutral-atom type store information in the energy levels of each trapped atom, and rubidium is among the most common choices.

Which metal refuses to form an alloy with rubidium, even though the two share a periodic-table group?

Lithium sits in the same group as rubidium yet will not alloy with it, while gold, iron, sodium and even liquid mercury all will.

Rubidium has served as a getter, a material that mops up stray gases, inside which electronic components?

Vacuum tubes work only if almost no gas remains inside, and reactive rubidium combines with the last traces of oxygen.

Radioactive rubidium-82 collects more in which growths than in nearby healthy tissue, helping doctors locate them?

Brain tumors weaken the barrier that normally keeps substances in the blood out of the brain, so the rubidium leaks in and lights them up.

Natural rubidium is just radioactive enough that, left in contact for 110 days, it will noticeably fog what?

Photographic film is exposed by the weak radiation from rubidium-87, the unstable isotope that makes up about 28% of the natural element.

Radioactive rubidium-82, which vanishes within minutes, is the tracer injected for which kind of hospital imaging?

A PET scan detects the positrons that rubidium-82 emits; its half-life is barely over a minute, so each dose is drawn fresh from a generator beside the scanner.

When rubidium metal reacts with water, which kind of strongly caustic rubidium compound is left dissolved?

Hydroxide is the product: rubidium hydroxide is a strong base, yet it is rarely used because cheaper relatives such as sodium hydroxide do nearly all the same jobs.

Rubidium vapor is the sensing element in some of the world's most sensitive instruments for measuring what?

Magnetic fields nudge the spinning atoms in the vapor and a laser reads the effect; such magnetometers can rival superconducting sensors of the same size.

Pure rubidium metal is usually produced by heating rubidium chloride at about 750 °C with which reactive metal?

Calcium pulls the chlorine away from the rubidium, a reaction run at low pressure; most other routes to such reactive metals need electrolysis.