Who coined the word 'atom'?
- A.Democritus
- B.Thomson
- C.E Rutherford
- D.John Dalton
Correct answer
Explanation
The correct answer is A, Democritus. The Greek philosopher Democritus, working in the fifth century before the common era, argued that matter could be divided only up to a limit, and he called that smallest indivisible particle atomos, from which the word atom comes. His was a philosophical claim, not an experimental one. Option B is wrong because J. J. Thomson discovered the electron in 1897 and proposed the plum pudding model of the atom. Option C is wrong because Ernest Rutherford performed the alpha-particle scattering experiment, discovered the nucleus and identified the proton, but the word was in use long before him. Option D is wrong because John Dalton gave the first scientific atomic theory in 1808, using the existing word rather than coining it. A quick way to keep these apart is that Democritus named the atom, Dalton theorised it, Thomson found what is inside it and Rutherford found its nucleus.
Read the full article: Atomic Structure and Periodic Table: Models and Trends
Practice Questions
View allWho among the following discovered the neutrons?
- A.J. Chadwick
- B.E. Goldstein
- C.Neils Bohr
- D.Ernest Rutherford
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James Chadwick discovered the neutron in 1932 by bombarding beryllium with alpha particles and showing that the radiation produced consisted of neutral particles of nearly the same mass as the proton.
Read the full explanation →Rutherford's alpha-particle scattering experiment on a thin gold foil led to which conclusion?
- A.Electrons are embedded in a sphere of positive charge
- B.The atom is indivisible
- C.Electrons revolve in fixed permitted orbits
- D.Almost all the mass and the positive charge lie in a tiny nucleus
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Most alpha particles passed straight through the foil, a few were deflected through small angles and about one in twenty thousand bounced back.
Read the full explanation →The maximum number of electrons that can be accommodated in the M shell is:
- A.8
- B.2
- C.18
- D.32
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The capacity of a shell is given by the formula 2n squared, where n is the number of the shell counted outward from the nucleus.
Read the full explanation →Alkali metals are assigned which group in the Modern Periodic Table?
- A.Second group
- B.Eighteenth group
- C.Third group
- D.First group
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The alkali metals are lithium, sodium, potassium, rubidium, caesium and francium. Each has a single electron in its outermost shell, loses it readily to form a positive ion, and therefore stands in group 1 of the modern periodic table.
Read the full explanation →Which of the following elements has the highest electronegativity?
- A.Fluorine
- B.Bromine
- C.Iodine
- D.Chlorine
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Electronegativity is the tendency of an atom to attract a shared pair of electrons towards itself. It increases from left to right across a period, as nuclear charge grows, and decreases down a group, as each new shell puts the outer electrons further from the nucleus.
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