As proposed by Dalton, which of the following symbol represents phosphorus ?

Q: What is the answer to NDA (II) 2023 GAT Q116?

D. Correct — D, the circle divided into three by lines radiating from its centre. Dalton's notation, set out in A New System of Chemical Philosophy (1808), gave every element a **circle** and distinguished them by what was drawn inside it. Non-metals got patterns — a dot, a bar, a cross, radiating lines — while most metals got a letter from the element's name. Phosphorus is the circle marked with the radiating lines, and that is what the official key selects. The other three can be ruled out on what Dalton used them for. The circle with a **cross** is his sign for **sulphur**. The circle with an **L** is his sign for **lead** — one of the letter-in-circle forms he reserved for metals, alongside C for copper. Neither of the two letter options names phosphorus at all.

(a)A circle with the letter P inside it
(b)A circle with the letter L inside it
(c)A circle divided into four by a cross
(d)A circle divided into three by lines radiating from its centre

Answer

Why

Correct — D, the circle divided into three by lines radiating from its centre. Dalton's notation, set out in A New System of Chemical Philosophy (1808), gave every element a circle and distinguished them by what was drawn inside it. Non-metals got patterns — a dot, a bar, a cross, radiating lines — while most metals got a letter from the element's name. Phosphorus is the circle marked with the radiating lines, and that is what the official key selects. The other three can be ruled out on what Dalton used them for. The circle with a cross is his sign for sulphur. The circle with an L is his sign for lead — one of the letter-in-circle forms he reserved for metals, alongside C for copper. Neither of the two letter options names phosphorus at all.

Why the others are wrong

(a)
A circle with the letter P inside it — The obvious trap: P is the modern symbol for phosphorus, but modern letter symbols are BERZELIUS's system of 1814, not Dalton's. Dalton's letter-in-circle forms belonged to metals, so a circled P is not his phosphorus.
(b)
A circle with the letter L inside it — This is Dalton's symbol for lead. He used a circled letter for several metals — L for lead, C for copper — and none of them stands for phosphorus.
(c)
A circle divided into four by a cross — This is Dalton's symbol for sulphur, the pattern most often reproduced alongside his dotted circle for hydrogen. It is a genuine Dalton sign, just for the wrong element.

Concept

John Dalton attached a circular symbol to each element because, in his atomic theory, the symbol stood for one atom of a definite mass rather than merely naming a substance. The system was pictorial: circles containing dots, bars, crosses or radiating lines for the non-metals, and circles containing a letter for most metals. It was replaced by Jons Jacob Berzelius's letter notation in 1814, which is the one still used.

The item is really about telling two notations apart. Every candidate knows P is phosphorus, and that is exactly why option (a) is offered — but the circled letter belongs to the wrong century's system for this element. Dalton's pictorial signs are a fixed, small set worth recognising: the dotted circle for hydrogen, the plain circle for oxygen, the filled circle for carbon, the crossed circle for sulphur. Once sulphur is placed at (c), the only remaining pattern is (d).

Key facts

Dalton set out his circular symbols in A New System of Chemical Philosophy, 1808.
Each symbol stood for ONE ATOM of definite mass, not just the element's name.
Non-metals took patterns inside the circle; many metals took a letter — L for lead, C for copper.
The circle with a cross is Dalton's sulphur.
Modern one- and two-letter symbols are Berzelius's system of 1814, not Dalton's.

What each printed circle stands for

(d) circle with lines radiating from the centre→Phosphorus — the answer

(b) circle containing L→Lead — Dalton's letter-in-circle form for a metal

(a) circle containing P→A letter symbol; modern P is Berzelius's notation, not Dalton's

Dalton drew patterns for non-metals and letters for metals — phosphorus is the radiating-line circle, option (d).

Study next

Dalton's atomic theory and his system of symbolsBerzelius and the modern letter notation of 1814Latin-derived symbols: Na, K, Fe, Cu, Ag, Au, Pb, Sn, HgLaws of chemical combination underlying Dalton's theory

Common traps

Choosing the circled modern letter for the element in question.
Crediting Dalton with the letter notation, which is Berzelius's.
Mixing up the crossed circle (sulphur) with other patterned circles.

NDA prints four of Dalton's circular signs and names an element — recall that letters inside circles were his metals, and match the remaining patterns against the small set of known non-metal signs.

Related PYQs

No directly related past PYQ was found.

Practice

practice — not a real PYQ
The modern system of representing elements by one or two letters was introduced by
- (a)John Dalton
- (b)Antoine Lavoisier
- (c)Jons Jacob Berzelius
- (d)Robert Boyle
Answer(c) Jons Jacob Berzelius — he introduced the alphabetic notation in 1814, replacing Dalton's circles.
practice — not a real PYQ
In Dalton's system of symbols, a circle with a cross inside it represented
- (a)hydrogen
- (b)oxygen
- (c)sulphur
- (d)carbon
Answer(c) sulphur — Dalton marked sulphur with a cross inside the circle.