Sodium is Number Eleven Trivia Quiz

Answer: The nucleus of a sodium atom contains eleven protons.

The periodic table organises the elements systematically according to the number of protons in the nucleus of each type of atom. They are also displayed in such a way that the elements in any given column have the same number of electrons in their outer shell, meaning that they have similar chemical properties.

The first row contains two elements (hydrogen and helium), which have electrons in the first (innermost) shell. The second row has another eight elements, which have a full innermost shell, and between one and eight electrons in the second shell. Sodium is the first element in the third row, and has one electron in its third shell.

This means that, like the other alkali metals, it readily loses its single electron to form positive ions in chemical reactions.

Answer: A liquid hydrocarbon such as kerosene

Sodium reacts with water to form sodium hydroxide and hydrogen gas. The heat released in the process ignites the hydrogen, often explosively (as seen in the image accompanying this question, which showed the result of adding a three-pound piece of sodium to a large container of water). Liquid bromine is a halogen, with seven outer shell electrons.

The word halogen comes from roots meaning salt forming - they react with alkali metals to form ionic compounds called salts - in this case, the salt sodium bromide would form. Even mercury, which is another metal, will react with sodium, forming an amalgam. An inert organic liquid such as kerosene is a viable solution.

Some facilities store sodium in a sealed container full of nitrogen gas, but that is not practical in all cases.

Answer: The acidity of the solution

Solid methyl orange forms an orange crystal, but the color of a solution in water varies from a vibrant red-orange (if the pH of the solution is under 3.1) to yellow (if the pH is above 4.4). The pH of a solution is a number indicating the concentration of hydrogen ions in the solution - the smaller the number, the more H+ there is, and the more acidic the solution. Because methyl orange changes color while the solution is still in the acidic range (less than 7), it is most useful when investigating acidic solutions.

In a titration, it will give the most accurate endpoint for the reaction between a strong acid and a weak base, since the solution will still be acidic at the equivalence point.

Answer: Sodium chloride

All of these compounds would be called a salt by a chemist, but in relation to human food, the term universally refers to sodium chloride. Sodium chloride, also known as halite, has the chemical formula NaCl - it is composed of an equal number of sodium ions (with a charge of +1) and chloride ions (with a charge of -1).

It is added to food both for the flavor it imparts and for its preservative properties. Salt produced by evaporating seawater or the water from salt lakes is called sea salt; salt produced by mining and crushing crystalline halite is called rock salt.

Answer: Washing soda

Other names for this useful cooking ingredient include bread soda, bicarb soda, and simply bicarb. It needs to be mixed with an acid in order to react and produce carbon dioxide gas, the bubbles of which get trapped in the dough to produce a fluffy texture. A side effect is a metallic taste, which becomes noticeable if you are overenthusiastic in adding the baking soda, trying for a super-light result, especially if the mixture is short on acid. To avoid this, many recipes call for the use of baking powder, which contains a mixture of sodium bicarbonate and a powdered acid such as tartaric acid.

On a less practical note, many children over the years have been entranced to see what happens when you place a paper-filled pouch of sodium bicarbonate onto a pool of vinegar inside a "rocket" which has a single open end. Once the vinegar soaks through the paper, the two compounds react to produce carbon dioxide gas, which is expelled through the open end, making the rocket rise (at least for a while).

Answer: As a water softener

Washing soda is also called soda ash, because it used to be obtained from the ashes produced by burning plants that grew in sodium-rich conditions, especially seaweeds. In solution, it competes with the dissolved magnesium and calcium ions that are responsible for creating what is called hard water. Detergents work with reduced effectiveness in hard water, so if you live in an area where the water has a lot of dissolved minerals, it is common practice to add sodium carbonate along with the detergent. A paste of sodium carbonate can also be used to remove some kinds of stain from clothing (and carpets), including red wine.

Interested in a home-spun method for cleaning your silver trophies? Using a nonreactive bowl (such as one made of glass, china or plastic, not metal), place your silver and some aluminum (or aluminium) foil in the bowl, and cover with a solution of washing soda and salt in hot water. The ensuing oxidation-reduction reaction will change the silver compound that has formed on the surface of your silver object (tarnish) to revert to silver, usually with the release of small amounts of hydrogen sulfide. The rotten egg smell will dissipate with time; the process can be accelerated by washing in a detergent and drying thoroughly.

Answer: Sodium hydroxide

Other chemicals may also be added, but the active ingredient in many drain cleaners is sodium hydroxide, also called caustic soda. It acts by reacting with the typical substances that form a clogged drain, breaking them down so that they can be flushed with the addition of more water.

The most common substances are some type of oil or fat, which is turned into a soapy material in the process, and the protein of hair, which is also readily hydrolysed, producing ammonia along with the carboxylate ion. (Of course, if the blockage has some other cause, this chemical approach will fail - you may need to call the plumber!)

Answer: Saponification

Saponification literally means making soap. Sodium hydroxide is a strong base - it dissolves in water to produce a very alkaline solution which is capable of breaking the bonds holding the organic acids to the central glycerol atom and making the trigylceride molecule.

The product is a soap, described as a salt of the organic acid - in this case, sodium stearate. The organic acid (often referred to as a fatty acid) has a very long carbon chain, and most of the stearate ion is therefore hydrophobic (meaning it does not dissolve readily in water).

The end where the carboxylic radical is, however, has a charge on it and is hydrophilic. This means that the ions tend to orient themselves so that part of each one is in the water, and the other part is in any grease or oil to be found in the vicinity.

This makes it easier for the oil and water to mix. Here ends the washing lesson.

Answer: Laundry

NaOCl is usually just called bleach, although most commercial bleaches also contain some other chemicals as well as 3-10% sodium hypochlorite. It is an effective stain remover in many cases, but can damage some fabrics, and overuse even on suitable fabrics can cause long-term weakening.

It can also be useful in removing some stains, such as tannin, from solid surfaces - hence its use to clean stained tea or coffee cups. Its antibacterial action makes it useful as a constituent of toilet cleaners. Care must be taken when mixing sodium hypochlorite with other materials, as some reactions will produce chlorine, a toxic gas.

Answer: Photographic film

Sodium thiosulfate is familiarly known as hypo (a contraction of its older name, hyposulphite of soda) or fixer to those engaged in developing and printing black and white photographs. The film used for black-and-white photography is covered with a gel containing a silver halide, such as silver bromide, which forms atoms of silver when exposed to light. Once started, this process will proceed slowly even after the light source has been removed, so that eventually everything goes black. The sodium thiosulfate dissolves the unreacted silver halide, stopping the reaction. This is called fixing the image.

Of course, as well as some film I am going to need an old-fashioned camera - my daughter's digital camera works on totally different principles, but that has to wait for another quiz.