40 Fun Facts About Alkaline Earth Metals

Which precious gemstone is a variety of beryl, the mineral that gave beryllium its name?

Emerald is beryl tinted by traces of chromium or vanadium. Pure beryl, the mineral beryllium is extracted from, has no colour at all.

The Radium Girls were factory workers poisoned by the glowing paint they applied to which products?

Watch dials needed such fine brushwork that the women were told to point the bristles with their lips, swallowing a little radium with every stroke.

Magnesium sulfate, a popular bath soak, is sold as a salt named after which English spa town?

Epsom, in Surrey, had a spring on its common that drew 17th-century visitors seeking cures. The bitter salt left behind when the water was boiled took the town's name.

The James Webb Space Telescope's beryllium mirrors are coated in a thin film of which metal?

Gold reflects infrared light superbly. Beryllium sits beneath it because the metal is light, exceptionally stiff and keeps its shape in the extreme cold of deep space.

Marie Curie's radium-contaminated papers are stored in boxes lined with which metal?

Lead blocks the radiation, and anyone who wants to consult the papers must wear protective clothing. Even her cookbooks are radioactive.

Which molecule, used by plants to capture sunlight, holds a single magnesium atom at its centre?

Chlorophyll holds magnesium where the haem in blood holds iron. Finding the metal there in 1906 was the first time magnesium had been detected in living tissue.

Beryllium was once called glucinium because some of its compounds have which taste?

Sweet was the verdict of early chemists, who identified beryllium compounds by tasting them. It was a hazardous habit, because the element is highly toxic.

Barium compounds are packed into fireworks to produce which colour when the shells burst?

Green is barium's signature in a flame, so reliable that chemists use the colour as a quick check for the element in an unknown sample.

Patients swallow a barium sulfate drink so their digestive tract shows up on which type of scan?

X-ray beams are strongly absorbed by barium. The drink is safe because barium sulfate barely dissolves, so the toxic metal passes through without being taken up.

Strontium is named after Strontian, a village where its mineral was first found, in which country?

Scotland's Strontian lies in the western Highlands, where 18th-century miners turned up an unfamiliar mineral that was named strontianite after the village.

The alkaline earth metals occupy which column of the periodic table, right beside the alkali metals?

Group 2 atoms each carry a pair of outer electrons that they give up readily, which is why these metals are reactive and always form ions with a double positive charge.

Which English chemist first isolated magnesium, calcium, strontium and barium, all during 1808?

Humphry Davy had already isolated sodium and potassium the year before, so his tally reached six new metals in about two years.

Which element did the Curies discover months before radium and name after Marie's homeland?

Polonium honours Poland, which at the time was partitioned between three empires and did not exist as an independent country. The Curies found it in the same ore as radium.

Almost all of the calcium in the human body, roughly 99 percent, is stored in which tissues?

Bones and teeth get their structure and strength from it, while the tiny remainder helps nerves carry messages around the body.

Which nutrient, made in skin exposed to sunlight, does the body need to absorb calcium from food?

Vitamin D raises the gut's uptake of calcium. It was discovered in 1922 during the search for the dietary cause of rickets in children.

Which rock, used to clad the Taj Mahal, is mostly recrystallised calcium carbonate?

Marble forms when heat and pressure deep underground recrystallise carbonate rock. Its famous veins and swirls come from impurities such as clay and iron oxides.

The White Cliffs of Dover are made of which soft, crumbly form of calcium carbonate?

Chalk is built from the microscopic shells of plankton that settled on an ancient sea floor, so the cliffs are essentially a graveyard of tiny sea creatures.

Radium decays directly into which radioactive gas, once known to scientists as radium emanation?

Radon is a dense noble gas that can be breathed in, which makes it responsible for much of the danger posed by radium in the environment.

Magnesium ribbon, which burns with a light like daylight, was first made in the 1860s for which craft?

Photography gained a bright artificial light from burning magnesium. In 1887 two German inventors turned it into flash powder, set off in a single bright burst.

Calcium is best known from milk and seashells, but what colour is the pure metal?

A silvery metal is the surprise: pure calcium is bright and shiny, but air quickly coats it in a dark layer, and it is far too reactive to occur uncombined in nature.

What do dissolved calcium and magnesium create at the tap, furring up kettles and resisting soap lather?

Hard water picks up both metals as it seeps through rock, which is why soap refuses to foam in it and softeners are sold to strip them out again.

Which flammable gas, burned in old miners' lamps, is made by dripping water onto calcium carbide?

Acetylene lamps were worn on miners' hats in the early twentieth century, and also served as lighthouse beacons and as headlights on early motor cars and bicycles.

Gypsum, a calcium sulfate mineral, is heated to make which powder used for casts on broken limbs?

Plaster of Paris is named after Montmartre, a hill in the north of the French capital, whose quarries long supplied the burnt gypsum.

Radium was once widely used in hospitals as a source of radiation for treating which disease?

Cancer treatment even gave radium a modern revival: the isotope radium-223 was approved in the United States in 2013 for prostate tumours that have spread.

Marie Curie's discovery and isolation of radium earned her a second Nobel Prize, in which field?

Chemistry made her the first person to win a Nobel Prize twice. Her earlier award, in physics, had been shared with her husband Pierre and Henri Becquerel.

Barium takes its name from a Greek word, also the root of baritone, with which meaning?

Heavy describes barium's dense ores, one of which is also known as heavy spar.

Calcium fizzes when dropped into water, leaving an alkaline solution and giving off which gas?

Hydrogen bubbles off faster further down the family: calcium reacts more quickly than magnesium but less quickly than strontium, while beryllium does not react with cold water at all.

Strontium salts go into emergency road flares because they burn with which colour of flame?

Red flares for roads and ships are often based on strontium nitrate, and the same family of salts supplies the deep scarlet in firework displays.

Which mineral, the softest on the Mohs scale and the basis of baby powder, is a magnesium silicate?

Talc defines the very bottom of the scale, with a value of 1. Ground up, often with corn starch, it becomes the familiar nursery powder.

Most of the world's baryte, the chief ore of barium, is used to weigh down the muds of which industry?

Oil drilling and gas wells swallow most of the baryte mined, far ahead of chemicals and paint fillers. The dense powder adds weight to the mud pumped down the hole.

Which newly developed technique first isolated four alkaline earth metals in 1808?

Electrolysis confirmed Lavoisier's suspicion that the alkaline 'earths' were compounds of unknown metals, which is how the family got its name.

James Chadwick discovered which particle in 1932 by studying radiation from bombarded beryllium?

Neutron radiation from beryllium had at first been taken for gamma radiation. Chadwick showed it was a stream of uncharged particles about as massive as the proton.

Beryllium copper tools are used around explosives and flammable gases because they avoid which hazard?

Sparks never fly from the alloy, which is also tough and nonmagnetic, making it a standard choice for hand tools in gunpowder works.

Berylliosis, a chronic disease of workers exposed to beryllium dust and fumes, attacks which organs?

Lungs can become sensitised to the metal in an allergic-type reaction, and symptoms may appear anywhere from weeks to tens of years after the first exposure.

Burning magnesium keeps blazing in water and carbon dioxide, so firefighters smother it with what instead?

Sand cuts off the air supply. Water and carbon dioxide both fail because the white-hot metal strips the oxygen out of them and carries on burning.

Which European mountain range shares its name with a calcium magnesium carbonate mineral?

The Dolomites were named after the mineral, which in turn honours Déodat de Dolomieu, the French geologist who described the rock in 1791.

The Curies extracted radium from tonnes of pitchblende, an ore mined chiefly for which other element?

Uranium ore typically yields only about a seventh of a gram of radium per ton, so even a tiny sample demanded an industrial quantity of rock.

Laser-cooled strontium atoms sit at the heart of some of the most precise examples of which instrument?

Clocks built on strontium count light waves at 429 terahertz, a far faster beat than the caesium standard manages, and that is what makes them so stable.

Which French chemist discovered beryllium in 1798, a year after he had discovered chromium?

Louis Nicolas Vauquelin was asked to analyse two gemstones whose crystals looked identical, and found the same unknown 'earth' hiding in both.

A barium mineral that glowed in the dark after roasting was named after which Italian city?

Bologna lies close to where Vincenzo Casciarolo dug up his specimens, which shone at night once he had ground them and heated them with charcoal.