Journey Through Atomic History

Who is credited with the discovery of the electron?

• Ernest Rutherford

• Niels Bohr

• J.J. Thomson

• Albert Einstein

What was the main conclusion from Rutherford's gold foil experiment?

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

• Electrons orbit the nucleus in fixed paths.

• Atoms can be divided into smaller particles.

• Energy levels of electrons are quantized.

What did Bohr's model of the atom suggest about electrons?

• Electrons move in random patterns around the nucleus.

• Electrons have properties of both particles and waves.

• Electrons travel in fixed orbits around the nucleus.

• The position of electrons cannot be determined precisely.

Which experiment led to the downfall of the plum pudding model of the atom?

• The cathode ray tube experiment

• The gold foil experiment

• The oil drop experiment

• The double-slit experiment

What is the significance of the Heisenberg Uncertainty Principle in the quantum mechanical model?

• It proves that electrons have a dual wave-particle nature.

• It states that the exact position and momentum of an electron cannot be simultaneously known.

• It defines the fixed orbits of electrons.

• It describes the nucleus as being composed of protons and neutrons.

Which of the following is NOT a postulate of Dalton's atomic theory, which is considered an early part of modern atomic theory?

• Atoms of different elements can combine in simple whole-number ratios to form compounds.

• Atoms are indivisible and indestructible.

• Atoms of the same element are identical in size, mass, and other properties.

• The nucleus of an atom is surrounded by a cloud of electrons.

What did the quantum mechanical model introduce that was absent in Bohr's model?

• The concept of energy levels

• The idea of a nucleus

• The electron cloud and probability distributions

• The fixed orbits of electrons

Which scientist was the first person responsible for proposing the idea of atoms?

• Democritus

• John Dalton

• Ernest Rutherford

• J.J. Thomson

• Niels Bohr

Which scientist proposed the idea that the electrons orbited the nucleus on fixed paths with designated energies?

• Democritus

• John Dalton

• Ernest Rutherford

• J.J. Thomson

• Niels Bohr

the smallest particle of an element that retains the chemical properties of that element

• ion
• isotope
• atom
• element