Timeline for the Atomic Model

What was the primary reason Democritus's hypothesis about indivisible particles was not widely accepted for a long time?

• His theory was too complex for the technology of the time.

• His ideas were overshadowed by Aristotle's widely accepted theory, which lacked scientific data.

• He lacked the support of other prominent philosophers.

• He proposed that matter was made of only two elements, which was incorrect.

Which statement accurately describes a key aspect of John Dalton's atomic theory?

• Atoms of different elements are identical in mass and properties.

• Compounds are formed when atoms combine in simple, whole-number ratios.

• Atoms can be created or destroyed during chemical reactions.

• Matter is composed of four fundamental elements: Earth, Air, Fire, and Water.

How did J.J. Thomson discover the electron?

• By observing the deflection of particles in a cathode ray tube by charged plates.

• By shooting positively charged particles at gold atoms.

• By analyzing the consistent ratios in which elements combine to form compounds.

• By hypothesizing that all matter is made of indivisible particles called "atomos."

What was a key characteristic of J.J. Thomson's "Chocolate Chip Cookie" model of the atom?

• A dense, positively charged nucleus at the center.

• Electrons orbiting the nucleus in specific energy levels.

• A uniform sphere of positive matter with negative electrons embedded within it.

• Indivisible, solid spheres that could not be broken down further.

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What did Rutherford's gold foil experiment reveal about the structure of an atom?

• Atoms are mostly empty space with a dense, positively charged nucleus.

• Electrons orbit the nucleus in fixed energy levels.

• Atoms are uniformly filled with positive matter and embedded electrons.

• Electrons exist in a cloud of probability around the nucleus.

What was a key characteristic of Bohr's atomic model?

• Electrons are randomly distributed throughout the atom.

• Electrons orbit the nucleus in specific, quantized energy levels.

• The atom is a solid sphere of uniform density.

• Electrons are found in a cloud of probability.

Bohr's atomic model, while introducing quantized energy levels, was limited because it only accurately described which element?

• Helium

• Oxygen

• Hydrogen

• Carbon

What concept did Schrödinger's cloud model introduce regarding the location of electrons?

• Electrons orbit the nucleus in fixed, planetary paths.

• Electrons are always found at a precise location at any given time.

• The probability of finding an electron within specific atomic orbitals.

• Electrons are uniformly spread throughout the atom.