Understanding Atomic Theory: A Historical Perspective

Who were the first to propose the concept of atoms?

• Leucippus and Democritus

• John Dalton

• Ernest Rutherford

• Niels Bohr

What did the ancient Greeks believe atoms were?

• Indivisible particles

• Small, charged particles

• Waves of energy

• Clusters of protons and neutrons

What did the law of conservation of mass state?

• Matter can neither be created nor destroyed

• Atoms are indivisible

• Energy is quantized

• Electrons have dual nature

What did Dalton contribute to atomic theory?

• Introduced quantum theory

• Proposed atoms are indivisible

• Identified the nucleus

• Discovered the electron

Who discovered the electron?

• J.J. Thomson

• Ernest Rutherford

• Niels Bohr

• Werner Heisenberg

What model did J.J. Thomson propose?

• Plum pudding model

• Cloud model

• Quantum model

• Planetary model

What was the significant finding of Rutherford's gold foil experiment?

• Existence of the nucleus

• Quantum nature of electrons

• Discovery of electrons

• Behavior of electromagnetic energy

What did Rutherford's experiment prove about the atom's structure?

• It contains only negative charges

• It is mostly empty space

• It is completely solid

• It has no nucleus

Who proposed the planetary model of the atom?

• Ernest Rutherford

• Niels Bohr

• J.J. Thomson

• Werner Heisenberg

How did Bohr's model differ from Rutherford's?

• It introduced the nucleus

• It discovered protons

• It suggested electrons have orbits

• It proposed atoms are mostly empty space