Circus of the Elements Trivia Quiz

Answer: bromine

Liquid bromine, Br2, atomic number 35, was isolated in 1826 by Antoine Jerome Balard, who was able to extract it from seawater. It is a very dense liquid (1 litre of it weighs over 3 kg!) with a distinctive deep brown colour and sharp odour. Bromine is a member of the group of the periodic table known as the halogens.

This group also includes chlorine (as found in salt, sodium chloride) and iodine. Mercury, while existing in its natural state as a liquid, is a metal, not a non-metal.

Answer: noble gases

The noble gases comprise the elements of group 8 (sometimes known as group 18 depending on the numbering system being followed). The naturally occurring elements of Group 8 are (in order of increasing atomic number) helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) and radon (Rn).

The noble gases are known for their chemical inertness, which is what gave rise to their group name. Their lack of reactivity is due to the fact that they all possess a full ("closed") outer shell of electrons, meaning that there is no incentive for them to combine with another element in order to achieve this favourable situation.

Some compounds of the noble gases are known (for example, XeF6), but by and large they are the standoffish group of the periodic table!

Answer: cesium

Cesium (Cs; also known as caesium) is one of the alkali metals (group 1) and has an atomic radius of 3.34 Angstroms (an Angstrom is 10^-10 of a metre). It was discovered jointly by Gustov Kirchoff and Robert Bunsen in Germany in 1860. Its name is derived from the Latin "caesius", meaning "sky blue", as its salts turn flames blue. Cesium is not the last member of the alkali metals - this honour goes to francium, whose atomic radius would be expected to be larger due to it containing more electrons.

However, at this stage, francium has only been obtained from the radioactive decay of actinium (and then decays to radium or astatine) and its atomic radius has yet to be determined.

Answer: tungsten

Tungsten (W), atomic number 74, is a transition metal with a boiling point of 5655 C (10211 F); its melting point is also a rather healthy 3407 C (6165 F)! It was jointly discovered in 1783 by Spanish scientists Fausto and Juan José de Elhuyar. Its name is derived from the Swedish "tung sten" ("heavy stone") and its chemical symbol from its German name wolfram.

Its high melting point makes it ideal for using it to make the filaments in light bulbs.

Answer: carbon

Carbon (C), atomic number 6, has a melting point of 3500 C (6332 F), although interestingly, its boiling point of 4827 C (8721 F) is less than that of tungsten (see Qu 4). Carbon is the basis on which our bodies are built: everything from our bones to our DNA contains carbon. Carbon has been known since ancient times and its name is derived from the Latin word "carbo" meaning "charcoal". Carbon is an element that is found in a number of physical forms.

These different physical forms of an element are called allotropes. Allotropes of carbon include graphite (used as the "lead" in pencils) and diamond (used as a gemstone).

Answer: hydrogen

Hydrogen (H), atomic number 1, is the lightest of all the elements with a density of only 0.0899 grams per litre (yes, that's _litre_!). Helium is next in line with a density of 0.1785 g/L. Hydrogen was discovered in England in 1766 by Henry Cavendish.

It has been calculated that, by mass, 73% of the universe is hydrogen (that's a lot of hydrogen!), making it the universe's most abundant element. A lot of this hydrogen is found in stars, where it is used as fuel; on earth, hydrogen is most commonly found in combination with oxygen as water and also in mines and oil and gas wells.

Answer: osmium

Osmium (Os), atomic number 76, has a density of 22.6 grams per millilitre, the same as iridium (that's seriously heavy - consider that water has a density of 1 g/ml). Iridium and osmium have been battling for the title of "heaviest element" for some time now; they have changed places a number of times (due to refinements in density measurement techniques), but to the third significant figure, their density is the same. Osmium was discovered in 1804 by Smithson Tenant in England.

Its name is derived from the Greek word "osme", meaning "odour" due to the metal's pungent smell.

It is derived from the same ores as platinum and has a variety of uses ranging from being used to tip the points of gold pens to being used in the filaments for electric lights.

Answer: fluorine

Fluorine (F), atomic number 9, has an electronegativity of 3.98 (on the Pauling electronegativity scale). This means that fluorine has a very high affinity for electrons and will tend to gain an electron to form a fluoride ion, F-. In general, non-metals tend to be electronegative, while metals tend to be the opposite (electropositive). Fluorine was discovered by Henri Moissan in France in 1886. Because of its high electronegativity, it is very reactive; it is used in refrigerants and also in toothpaste as sodium fluoride (NaF) and can also be found in Teflon, which is a polymer of tetrafluoroethylene.

Answer: transition metals

The transition metals are a group of metals in the centre of the periodic table encompassing Groups 3-12 inclusive (group numbers based on the new IUPAC system). The transition metals are known for their variable oxidation states; for example, iron (Fe) can exist in either a +2 or a +3 oxidation state while chromium (Cr) can exist in oxidation states of +2, +3 and +6. Transition metal ions also form compounds called metal complexes, which are often coloured due to the outermost d-electrons present in the metal ion; for example, complexes of nickel(II) are green in colour.

Answer: astatine

Astatine (At), atomic number 85, is the earth's rarest element, with only 25 g in total occurring naturally. It is so rare that it is usually sourced by bombarding the element bismuth with alpha particles. Astatine is a member of the halogens group and was discovered in 1940.

Its name is derived from the Greek word "astatos" meaning "unstable", an entirely suitable name as it is a radioactive element with a half-life of only 8.1 hours. Well, tonight's performance of Circus of the Elements is over; hope you enjoyed the show!