1.3 The development of the model of the atom

• What does atomic structure refer to?

  Arrangement of subatomic particles
• Rutherford's nuclear model suggests that atoms are mostly empty space.


  True
• Dalton's solid sphere model states that all atoms of the same element are identical
• What is the key feature of Thomson's plum pudding model?

  Uniform positive sphere
• Which experiment led to the development of Rutherford's nuclear model?

  Gold Foil Experiment
• What did Rutherford's nuclear model revolutionize in the understanding of atomic structure?

  Central nucleus and electron shells
• The total positive charge in the Thomson's plum pudding model equals the total negative charge

  True
• What did the undeflected passage of most alpha particles through the gold foil indicate?

  Atoms are mostly empty
• Steps of the Gold Foil Experiment

  1️⃣ Direct alpha particles at thin gold foil

  2️⃣ Observe that most particles pass through undeflected

  3️⃣ Note that some particles are deflected

  4️⃣ Conclude the existence of a dense, positive nucleus
• Electrons can jump between energy levels by absorbing or emitting energy


  True
• What describes the location of electrons in the quantum mechanical model?

  Probability distributions
• Match the atomic model with its key description:

  Dalton's Solid Sphere ↔️ Tiny, indivisible spheres

  Thomson's Plum Pudding ↔️ Positive sphere with electrons

  Rutherford's Nuclear ↔️ Dense, positive nucleus

  Bohr's Atomic ↔️ Fixed energy levels
• Dalton's solid sphere model proposes that atoms are tiny, solid, and indivisible
• Arrange the following atomic models in chronological order:

  1️⃣ Dalton's solid sphere model

  2️⃣ Thomson's plum pudding model

  3️⃣ Rutherford's nuclear model

  4️⃣ Bohr's atomic model
• In Thomson's plum pudding model, the total positive charge equals the total negative charge
• In Rutherford's Gold Foil Experiment, most alpha particles were deflected by the positively charged nucleus.

  False
• What does the Thomson's plum pudding model describe the atom as?

  Positive sphere with electrons
• What model did the Thomson's plum pudding model replace?

  Dalton's solid sphere
• Rutherford's nuclear model states that the nucleus contains most of the atom's mass

  True
• Bohr's atomic model proposed that electrons orbit the nucleus in specific energy levels
• Match the atomic model with its key feature:

  Rutherford's Nuclear Model ↔️ Dense, positive nucleus

  Bohr's Atomic Model ↔️ Fixed energy levels

  Quantum Mechanical Model ↔️ Electrons in orbitals
• Electrons in the quantum mechanical model occupy discrete energy levels


  True
• How does Thomson's plum pudding model describe the atom?

  Uniform positive sphere with electrons
• Match the subatomic particle with its charge, mass, and location:

  Proton ↔️ +1, 1 amu, Nucleus

  Neutron ↔️ 0, 1 amu, Nucleus

  Electron ↔️ -1, ≈0 amu, Orbiting shells
• Dalton's solid sphere model accurately describes the internal structure of an atom.

  False
• Thomson's plum pudding model marked a significant advancement over Dalton's solid sphere model.


  True
• Rutherford's nuclear model proposed the existence of a small, dense, and positively charged nucleus
• According to the Thomson's plum pudding model, the atom is a sphere of positive charge
• Rutherford's nuclear model emerged from the **Gold Foil Experiment
• What charge does the nucleus have in Rutherford's nuclear model?

  Positive
• What happens to an electron's energy as it remains in a fixed energy level in Bohr's model?

  It remains constant
• In the quantum mechanical model, electrons are described by three-dimensional regions called orbitals
• Arrange the atomic models in chronological order of their development

  1️⃣ Dalton's Solid Sphere

  2️⃣ Thomson's Plum Pudding

  3️⃣ Rutherford's Nuclear

  4️⃣ Bohr's Atomic

  5️⃣ Quantum Mechanical