#P5.1.1
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 almost all of the mass in the nucleus
#P5.1.2
describe how and why the atomic model has changed over time to include the main ideas of Dalton, Thomson, Rutherford and Bohr
#P5.1.3
recall the typical size (order of magnitude) of atoms and small molecules
#P5.1.4
recall that atomic nuclei are composed of both protons and neutrons, and that the nucleus of each element has a characteristic positive charge
#P5.1.5
recall that nuclei of the same element can differ in nuclear mass by having different numbers of neutrons, these are called isotopes
#P5.1.6
use the conventional representation to show the differences between isotopes, including their identity, charge and mass
#P5.1.7
recall that some nuclei are unstable and may emit alpha particles, beta particles, or neutrons, and electromagnetic radiation as gamma rays
#P5.1.8
relate emissions of alpha particles, beta particles, or neutrons, and gamma rays to possible changes in the mass or the charge of the nucleus, or both
#P5.1.9
use names and symbols of common nuclei and particles to write balanced equations that represent the emission of alpha, beta, gamma, and neutron radiations during radioactive decay
#P5.1.10
explain the concept of half-life and how this is related to the random nature of radioactive decay
#P5.1.11
calculate the net decline, expressed as a ratio, in a radioactive emission after a given (integral) number of half-lives
#P5.1.12
interpret activity-time graphs to find the half-life of radioactive materials