The Atom

• What are the three subatomic particles that make up an atom?

  Protons, neutrons, and electrons
• What is the relative mass of protons and neutrons compared to electrons?

  Protons and neutrons are heavy, while electrons have hardly any mass
• What is the charge of protons and neutrons?

  Protons are positively charged, and neutrons are neutral
• How is the mass of protons and neutrons measured?

  It is measured on a scale where the mass of a proton or neutron is 1
• What is the relative charge of electrons?

  Electrons are negatively charged
• Where is the nucleus located in an atom?

  The nucleus is in the middle of the atom
• What particles are contained in the nucleus?

  The nucleus contains protons and neutrons
• Why does the nucleus have a positive charge?

  It has a positive charge because of the protons
• How much mass is concentrated in the nucleus of an atom?

  Almost the whole mass of the atom is concentrated in the nucleus
• What is the radius of the nucleus?

  The radius of the nucleus is between about $10^{-16} \text{ m}$ and $10^{-14} \text{ m}$
• How do electrons move in relation to the nucleus?

  Electrons move around the nucleus in electron shells (or orbitals)
• What is the charge of electrons?

  Electrons are negatively charged
• What determines the size of an atom?

  The volume of the electron orbitals determines the size of the atom
• What is the atomic radius of an atom?

  The atomic radius is about $10^{-10} \text{ m}$
• What are molecules made of?

  Molecules are made up of two or more atoms
• Can molecules be made of the same element?

  Yes, molecules can be made of the same element, like hydrogen
• What is an example of a molecule made of different elements?

  An example is ammonia
• How long are the bonds that form between simple molecules?

  The bonds are generally a similar length to the atomic radius, about $10^{-10} \text{ m}$
• What are nanoparticles made of?

  Nanoparticles are typically made of around 100 atoms
• What is the size range of nanoparticles?

  Nanoparticles range from 1 nm to 100 nm in size
• What is 1 nanometre in metres?

  1 nanometre is $10^{-9} \text{ metres}$
• What is the relationship between nanometres and metres?

  1 nanometre is $10^{-9} \text{ metres}$
• What are the characteristics of protons, neutrons, and electrons?

  • Protons: heavy, positively charged
  • Neutrons: heavy, neutral
  • Electrons: tiny, negatively charged, virtually no mass
• What is the structure of an atom?

  • Nucleus: contains protons and neutrons, positive charge
  • Electrons: move around the nucleus in orbitals, negatively charged
• What is the difference between simple molecules and nanoparticles?

  • Simple molecules: made of two or more atoms, similar length to atomic radius (~$10^{-10} \text{ m}$)
  • Nanoparticles: made of around 100 atoms, size range from 1 nm to 100 nm