Atomic Structure

• What are gold and carbon classified as?

  They are classified as different kinds of elements.
• What is an atom?

  An atom is the smallest particle of an element that retains its chemical properties.
• What are different elements made from?

  Different elements are made from different atoms.
• What is the primary composition of an atom?

  An atom is mostly empty space and contains three subatomic particles.
• What is a molecule?

  A molecule is made from two or more atoms joined together.
• How are atoms in a molecule joined together?

  They are joined by attractive forces called chemical bonds.
• What are the two types of particles that make up the nucleus of an atom?

  Protons and neutrons.
• What is a molecule made from two oxygen atoms called?

  The molecule is called oxygen (O₂).
• Where are electrons located in an atom?

  Electrons surround the nucleus in shells.
• What is a carbon dioxide molecule made from?

  A carbon dioxide molecule is made from a carbon atom and two oxygen atoms.
• How does the radius of a nucleus compare to the radius of an atom?

  The radius of a nucleus is about 100,000 times less than the radius of an atom.
• What are the relative masses and charges of protons, neutrons, and electrons?

  • Proton:
  • Relative mass: 1
  • Relative charge: +1
  • Neutron:
  • Relative mass: 1
  • Relative charge: 0
  • Electron:
  • Relative mass: 0.0005
  • Relative charge: -1
• Can atoms in a molecule be the same?

  No, atoms in a molecule can be different.
• What is the atomic radius of an atom?

  The atomic radius is half the diameter of an atom.
• What is bond length?

  Bond length is the distance between the centres of two joined atoms.
• What are the typical sizes of atomic radii and bond lengths?

  They are typically around $10^{-10} m$.
• What is the oxygen-oxygen bond length?

  The oxygen-oxygen bond length is $1.21 \times 10^{-10} m$.
• How many metres is one nanometre (1 nm)?

  One nanometre is $1 \times 10^{-9} m$.
• What is the atomic radius for oxygen in nanometres?

  The atomic radius for oxygen is $0.073 \text{ nm}$.