1.1

• What are the smallest parts of an element that can exist?

  Atoms
• What is the radius of an atom?

  0.1 nanometres
• What distinguishes elements from compounds?

  Elements are made up of atoms with the same atomic number, while compounds contain two or more different elements.
• What are isotopes?

  Isotopes are atoms with the same number of protons but different numbers of neutrons.
• How is relative atomic mass calculated?

  It is calculated using the masses and abundances of each isotope.
• What was the initial belief about the structure of atoms?

  Atoms were believed to be tiny indivisible spheres.
• What did the discovery of electrons lead to in atomic theory?

  It led to the development of the Plum Pudding model.
• What was the outcome of the alpha particle scattering experiment?

  It led to the development of the Nuclear model of the atom.
• What did Bohr suggest about electron arrangement?

  Bohr suggested that electrons orbit the nucleus in shells.
• Who discovered protons and neutrons?

  James Chadwick
• What is the maximum number of electrons in the first three shells of an atom?

  2 in the first shell, 8 in the second shell, and 8 in the third shell.
• What are the relative masses of protons, neutrons, and electrons?

  Protons: 1, Neutrons: 1, Electrons: Very small
• What does the mass number represent?

  The mass number is the sum of protons and neutrons in an atom.
• What is the atomic number of an atom?

  The atomic number is the number of protons in an atom.
• What are the methods of separating mixtures?

  • Filtration
  • Crystallisation
  • Distillation
  • Chromatography
  • Simple and Fractional
• Describe the evolution of atomic models.

  1. Tiny undividable spheres
  2. Plum Pudding model (discovery of electrons)
  3. Nuclear model (alpha particle scattering)
  4. Bohr model (electrons in shells)
  5. Discovery of protons and neutrons (James Chadwick)
• What is the electronic configuration for nitrogen?

  2, 5 (2 electrons in the first shell, 5 in the second)

  
• What is the charge of protons, neutrons, and electrons?

  • Protons: Positively charged
  • Neutrons: Neutral charge
  • Electrons: Negatively charged
• What is the significance of filling electron shells?

  • Electrons occupy the lowest energy levels first.
  • Inner shells are filled before outer shells.