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50 free Sodium trivia questions with answers — science & nature quiz, new questions added Aug 2026.
Sodium trivia for chemistry students, pub-quiz teams and anyone who has watched a lump of it fizz across a lab sink. This quiz covers the element itself: atomic number 11, the soft silvery metal you can cut with a knife and must keep under oil, the single stable isotope, the Arabic and Egyptian words behind 'sodium' and 'Na', and Humphry Davy's 1807 experiment that first isolated it. It explains the yellow flame and the D line that lights up street lamps and laser guide stars, and the Downs cell that makes the metal today. It then moves to the compounds and the biology: table salt, baking soda, washing soda, lye and soap, natron and mummies, MSG and umami, the sodium-potassium pump that eats a fifth of your energy, hyponatremia in marathon runners, and daily intake limits. It closes with sodium in industry and history: fast-reactor coolant, engine valves, airbags, the Solvay process, Wieliczka's salt mine and Gandhi's Salt March. Questions range from easy to expert, and every answer was checked against a reference page and carries its source. If you enjoy this quiz, try our periodic table, chemistry and salt quizzes next.
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Q 01What is sodium's atomic number?
11
It sits in group 1 of the periodic table, one electron beyond the noble gas neon.
Q 02Sodium's chemical symbol Na comes from natrium, a Neo-Latin word derived from what?
The Egyptian mineral natron
Natron is a natural salt of hydrated sodium carbonate that the Egyptians dug from Wadi El Natrun.
Q 03The word 'sodium' itself is thought to come from the Arabic 'suda', meaning what?
Headache
Medieval Europeans used sodanum, a sodium compound, as a headache remedy.
Q 04Who first isolated sodium metal in 1807?
Humphry Davy
He used electrolysis of sodium hydroxide, and isolated potassium the same year.
Q 05Which Swedish chemist first published the abbreviation Na for sodium, in 1814?
Jons Jakob Berzelius
A German chemist had proposed the name 'Natronium' for Davy's discovery in 1809.
Q 06How is bulk sodium metal usually stored?
Under oil or an inert gas
Exposed to air it forms sodium oxides; a knife cuts the soft metal easily.
Q 07What colour does sodium give to a flame?
Yellow
Excited electrons dropping from the 3p to the 3s orbital emit light at the D line, about 589 nanometres.
Q 08Sodium's D line is named after the letter assigned to it by which scientist in 1814?
Joseph von Fraunhofer
He was mapping the dark absorption lines of the solar spectrum, now named Fraunhofer lines.
Q 09How many stable isotopes does sodium have?
One
Twenty isotopes are known; sodium-22 lasts 2.6 years and sodium-24 about 15 hours, the rest under a minute.
Q 10Sodium-23 is forged in stars by fusing two atoms of which element?
Carbon
The carbon-burning process needs temperatures above 600 million kelvin and a star of at least three solar masses.
Q 11Sodium is the sixth most abundant element in the Earth's crust. Where does it rank among metals?
Fourth
Aluminium, iron, calcium and magnesium come ahead of it; potassium sits just behind.
Q 12What is the melting point of sodium?
98 C
It boils at 883 C; both are lower than lithium's but higher than potassium's, following the trend down group 1.
Q 13What two products form when the metal reacts with water?
A hydroxide and hydrogen gas
High-speed footage suggests the resulting explosion is a Coulomb explosion driven by charge repulsion.
Q 21Low-pressure sodium lamps, long used for street lighting, give off what kind of light?
Monochromatic yellow-orange
They are extremely efficient but make it impossible to see colours at night.
Q 22At what altitude is the sodium layer that astronomers fire lasers at to create artificial 'guide stars'?
90 km
The mesospheric sodium layer is fed by meteors; the glowing spot helps adaptive optics correct for turbulence.
Q 23Sodium has been detected in the thin exospheres of the Moon and which planet?
Mercury
The strong D line makes the element easy to spot across the Solar System and in cool stars.
Q 14Under enormous pressure, around 3 megabars, sodium metal becomes what?
A clear transparent solid
At 1.5 megabars it turns black, at 1.9 transparent red; all these high-pressure forms are insulators.
Q 15Metallic sodium is produced industrially by electrolysing molten salt in apparatus named after whom?
Downs
Calcium chloride is added to lower the melting point below 700 C; the process was patented in 1924.
Q 16Metallic sodium was first made commercially in the 19th century as a step in producing which other metal?
Aluminium
The Hall-Heroult process later made aluminium by electrolysis, ending the demand for large quantities of sodium.
Q 17Sodium's alloy with potassium, NaK, is notable for being what at room temperature?
A liquid
It is used as coolant in reactors that must shut down often, because it will not solidify in the pipes.
Q 18Molten sodium is used as the coolant in which type of nuclear power plant?
Fast neutron
Its high boiling point lets the reactor run at normal pressure, but it explodes on contact with water.
Q 19The first nuclear reactor ever to generate electricity, EBR-I in 1951, was cooled by what?
Sodium-potassium alloy
The 0.2-megawatt experimental breeder reactor achieved criticality in 1950 and demonstrated nuclear breeding.
Q 20In high-performance engines, sodium is sealed inside which component to carry heat away?
Poppet valve stems
The partly filled stem works as a heat pipe to cool the valve.
Q 24Sodium chloride occurs naturally as which mineral?
Halite
Sodium and chlorine are the most common dissolved elements by weight in the oceans.
Q 25Roughly what percentage of table salt by mass is sodium?
39%
So one gram of salt carries about 393 milligrams of sodium; a teaspoon holds around 2.3 grams of sodium.
Q 26The American Heart Association recommends no more than how much sodium per day?
1.5 g
The average American consumes about 3.4 grams; the US tolerable upper limit is 2.3 grams.
Q 27The sodium-potassium pump moves how many sodium ions out of a cell for every ATP molecule it uses?
Three
Two potassium ions come in for every three sodium ions expelled, keeping sodium ten times higher outside the cell.
Q 28Which Danish scientist discovered the sodium-potassium pump in 1957 and won a Nobel Prize for it in 1997?
Jens Christian Skou
The enzyme is found in the membrane of every animal cell.
Q 29The sudden inflow of sodium ions into a nerve cell through voltage-gated channels produces what?
An action potential
Sodium is the main positive ion in the fluid outside cells and sets its osmotic pressure.
Q 30Hyponatremia, common among marathon runners, is a blood sodium level below what?
135 mmol/L
Drinking too much water during endurance events is a classic cause.