CDS (II) 2023 General Knowledge · Question 6 of 120

Correct — C, Au, Sn, Pb. Three of the metals humanity has worked longest keep symbols taken from their Latin names rather than their English ones, which is exactly why this item exists. Gold is Au, from aurum. Tin is Sn, from stannum. Lead is Pb, from plumbum — the same root that gives us plumbing, because Roman water pipes were made of it. Option (c) is the only line that gets all three right. The other three options each swap in a symbol that belongs to a different element: Ga is gallium, At is astatine, Sb is antimony from stibium, and Le is not the symbol of any element at all.

• (a)Ga, Sb, Pb — Only lead survives. Ga is gallium, a soft metal that melts in the hand, and Sb is antimony from stibium — neither is gold or tin.
• (b)At, Sn, Le — Tin is right and the other two are not. At is astatine, the rarest naturally occurring element on Earth, and Le is not an accepted symbol for any element.
• (d)Au, Sb, Pb — The near-miss the paper is really testing. Gold and lead are correct, but the middle symbol is antimony rather than tin — Sb against Sn, one letter apart and both drawn from Latin.

A chemical symbol is a one- or two-letter shorthand for an element, written with the first letter capital and the second, if any, in lower case. Most come from the element's English or international name, but eleven of them come from Latin or other older names, and those are the ones examiners return to: sodium Na from natrium, potassium K from kalium, iron Fe from ferrum, copper Cu from cuprum, silver Ag from argentum, tin Sn from stannum, gold Au from aurum, mercury Hg from hydrargyrum, lead Pb from plumbum, antimony Sb from stibium and tungsten W from wolfram.

There is no reasoning route here, only recall, so the efficient move is to learn the Latin-derived list as a block rather than element by element. Notice the design of the options: every one of them offers a symbol that is real but belongs to somebody else, so a candidate who is sure of only two of the three metals can still be led into option (a) or option (d). The pair worth drilling is Sn and Sb, since both begin with S, both come from Latin, and swapping them is what separates option (c) from option (d). One printed slip is visible in the stem itself — the paper writes 'Which one among the following are the correct symbols', mixing a singular subject with a plural verb. It changes nothing about what is being asked.

• Gold is Au from the Latin aurum, tin is Sn from stannum, and lead is Pb from plumbum.
• Sb is antimony, from stibium; Ga is gallium; At is astatine — all three appear in this item as decoys.
• A chemical symbol is written with the first letter in capital and any second letter in lower case, a convention credited to the Swedish chemist Jöns Jacob Berzelius.
• Other Latin-derived symbols on the same list are Na sodium, K potassium, Fe iron, Cu copper, Ag silver, Hg mercury and W tungsten.
• Gold, silver, copper, tin, lead, iron and mercury are the seven metals of antiquity, which is why their names — and their symbols — predate modern chemistry.

• Confusing Sn (tin) with Sb (antimony); both come from Latin and both start with S.
• Assuming a symbol must begin with the first letter of the English name, which fails for gold, tin, lead, sodium, potassium, iron, copper, silver, mercury and tungsten.
• Writing a two-letter symbol with both letters capitalised, which changes its meaning — CO is carbon monoxide, Co is cobalt.

As a direct symbol-to-element match, as a 'which pair is correctly matched' item, or embedded in a formula-writing question where the wrong symbol wrecks the formula.

• practice — not a real PYQ

  The chemical symbols Fe, Ag and Hg stand respectively for

  • (a)iron, silver and mercury
  • (b)iron, gold and magnesium
  • (c)fluorine, silver and mercury
  • (d)iron, argon and hydrogen

  Answer(a) iron, silver and mercury — from the Latin names ferrum, argentum and hydrargyrum.

• practice — not a real PYQ

  Which one of the following elements has a chemical symbol derived from the Latin word 'stannum'?

  • (a)Antimony
  • (b)Strontium
  • (c)Tin
  • (d)Sulphur

  Answer(c) Tin — stannum gives Sn. Antimony's Sb comes from stibium, which is the pair most often confused with it.