C1.2 Atomic structure

• What is the focus of section C1.2 in the study material?

  Atomic structure
• What are atoms and molecules?

  Atoms are the basic units of matter, while molecules are formed when two or more atoms bond together.
• What is the typical bond length for an oxygen-oxygen bond?

  121 x $10^{-12}$ m
• How does the bond length relate to the size of atoms?

  The bond length is the distance between the nuclei of two bonded atoms, which reflects their size and the strength of the bond.
• What is the relationship between the number of protons and electrons in a neutral atom?

  In a neutral atom, the number of protons equals the number of electrons.
• How many subatomic particles do atoms have?

  Atoms have protons, neutrons, and electrons.
• What are isotopes?

  Isotopes are variants of a chemical element that have the same number of protons but different numbers of neutrons.
• How do you calculate the number of neutrons in an isotope?

  Subtract the atomic number from the mass number.
• What happens to the number of electrons when an atom becomes an ion?

  The number of electrons changes, either increasing or decreasing depending on whether it gains or loses electrons.
• What did Dalton contribute to atomic theory?

  Dalton proposed that all matter is made of atoms, which are indivisible and indestructible.
• What was Rutherford's contribution to atomic theory?

  Rutherford discovered the nucleus and proposed that atoms consist mostly of empty space.
• What did Thomson discover about the atom?

  Thomson discovered the electron and proposed the plum pudding model of the atom.
• What did Bohr contribute to atomic theory?

  Bohr proposed that electrons orbit the nucleus at fixed distances, leading to the planetary model of the atom.
• What are the key developments in atomic theory from Dalton to Bohr?

  • Dalton: Atoms are indivisible and indestructible.
  • Thomson: Discovered the electron; proposed the plum pudding model.
  • Rutherford: Discovered the nucleus; proposed that atoms are mostly empty space.
  • Bohr: Proposed fixed orbits for electrons around the nucleus.
• Why did many designs of the 19th century reject the atomic theory?

  Many designs rejected atomic theory due to a lack of experimental evidence and understanding of atomic structure.
• What is the significance of the Periodic Table in relation to atomic theory?

  • Organizes elements based on atomic number.
  • Predicts properties of elements.
  • Reflects the periodic nature of elements.