#C2.1.1
describe how and why the atomic model has changed over time to include the main ideas of Dalton, Thomson, Rutherford and Bohr
#C2.1.2
describe the atom as a positively charged nucleus surrounded by negatively charged electrons, with the nuclear radius much smaller than that of the atom and with most of the mass in the nucleus
#C2.1.3
recall relative charges and approximate relative masses of protons, neutrons and electrons
#C2.1.4
estimate the size and scale of atoms relative to other particles
#C2.1.5
recall the typical size (order of magnitude) of atoms and small molecules
#C2.1.6
relate size and scale of atoms to objects in the physical world
#C2.1.7
calculate numbers of protons, neutrons and electrons in atoms, given atomic number and mass number of isotopes or by extracting data from the Periodic Table