CDS (II) 2020 General Knowledge · Question 97 of 120

Correct — C, Jöns Jacob Berzelius. The symbols chemistry actually uses — one or two letters taken from the element's name, the first capitalised, the second small — were introduced by the Swedish chemist Berzelius in 1814. His system is what gives us H, O, Na for natrium, K for kalium, Fe for ferrum and Ag for argentum, and it made a chemical formula something that could be written in a line of ordinary type and read anywhere. The rival scheme it replaced was Dalton's: circles filled with dots, bars and letters, one distinct picture per element. Dalton's symbols carried quantitative meaning, each standing for one atom of a definite mass, but they had to be drawn rather than typed and became unusable as the list of known elements lengthened. Berzelius kept Dalton's idea that a symbol denotes a definite quantity of the element and threw away the pictures.

• (a)John Dalton — The near-miss, and a defensible reading of a loosely worded stem. Dalton did use symbols for elements first, in the early 1800s, and used them in a strict quantitative sense — but they were pictorial, circle-based signs, not the letter symbols the question is asking about. The letter notation is Berzelius's, and that is what the key marks.
• (b)Antoine Lavoisier — Lavoisier is remembered for the law of conservation of mass, for showing that combustion is combination with oxygen and demolishing the phlogiston theory, and for the first systematic naming of substances — but the naming reform of 1787 gave chemistry its words, not its letter symbols.
• (d)Robert Boyle — Boyle belongs to the seventeenth century, well before any of this. He is remembered for the pressure-volume law of gases and for defining an element as a substance that cannot be broken down further.

A chemical symbol is a one- or two-letter abbreviation for an element, with the first letter capital and the second, if there is one, lower case. Most are taken from the English name, but eleven of them come from Latin: Na from natrium, K from kalium, Fe from ferrum, Cu from cuprum, Ag from argentum, Au from aurum, Pb from plumbum, Sn from stannum, Sb from stibium, Hg from hydrargyrum and W from wolfram. The symbol is more than shorthand — it stands for one atom of the element, which is what lets formulae and balanced equations carry quantitative meaning.

The stem as printed — 'Symbol of element was introduced by' — is grammatically clipped and does not specify which kind of symbol, which is exactly where the difficulty lies, because two of the four men on the list have a claim. Read it as the modern letter symbol and Berzelius is the answer without argument; read it as 'the first person to use any symbol at all for an element' and Dalton has a case. The official key marks C, and the reasoning behind it is that Dalton's circles were pictorial signs while Berzelius created the alphabetic notation of 1814 that chemistry has used ever since. Worth noting that the paper drops the article before 'element', an incidental printing slip that does not change what is being tested.

• Berzelius introduced the modern alphabetic notation for elements in 1814: one or two letters from the name, the first capitalised.
• Dalton's earlier symbols were pictorial — circles marked with dots, lines and letters — and each stood for one atom of a definite mass.
• Eleven common symbols come from Latin names, among them Na for natrium, K for kalium, Fe for ferrum and Ag for argentum.
• Lavoisier's contribution to nomenclature was the systematic naming of compounds and the overthrow of phlogiston, not the letter symbols.
• Berzelius also determined atomic weights for a large number of elements and discovered cerium, selenium and thorium.

• Choosing Dalton because he used symbols first — the letter notation is Berzelius's.
• Writing a two-letter symbol with both letters capital, as CO for cobalt when CO is carbon monoxide and cobalt is Co.
• Assuming every symbol comes from the English name; sodium, potassium, iron, silver, gold, lead and tin do not.

As a scientist-to-contribution match, or by asking for the Latin origin of a particular symbol, or as a statement item on Dalton's atomic theory.

No directly related past PYQ was found.

• practice — not a real PYQ

  The symbol K for potassium is derived from which of the following names?

  • (a)Kalium
  • (b)Natrium
  • (c)Plumbum
  • (d)Stibium

  Answer(a) Kalium — the Latin name of potassium. Natrium gives Na, plumbum gives Pb and stibium gives Sb.

• practice — not a real PYQ

  Which one of the following is credited with the law of conservation of mass?

  • (a)Robert Boyle
  • (b)Antoine Lavoisier
  • (c)Jöns Jacob Berzelius
  • (d)Amedeo Avogadro

  Answer(b) Antoine Lavoisier — he established that mass is neither created nor destroyed in a chemical reaction.