Assessment criteria. Units 9 and 12: Atoms, molecules, states of matter, hydrosphere.

Unit 9

1. Explain why ice (solid water) floats on liquid water and why this is important for aquatic life.
2. Explain why we find water in most of the solutions.
3. Describe the processes that take place in the water cycle.
4. Suggest ways to save water.

Unit 12

1. Know the names of the changes of state: fusion, evaporation, solidification, condensation, sublimation, inverse sublimation.
2. Describe and sketch how particles are arranged in a solid, in a liquid and in a gas.
3. Given the name (or symbol) of an atom, its atomic number and its atomic mass, determine the number of protons, neutrons, and electrons and build the atom.
4. Given the name of these elements give the symbol and viceversa: Hydrogen, Oxygen, Iron, Carbon, Helium, Neon, Fluorine, Sodium, Chlorine.
5. Describe a molecule as a particle made up by the union of several atoms.
6. Know the formula of these molecules and build them: water, methane, carbon dioxide, carbon monoxide, molecular oxygen, molecular hydrogen, ammonia.
7. Define element and compound.
8. Classify substances into these groups and give an example of each type:

• Pure substances.
  • Elements.
    • Atomic.
    • Molecular.
    • With a crystal structure.
  • Compounds.
    • Molecular.
    • With a crystal structure.
• Mixtures.
  • Homogeneous.
  • Heterogeneous.