Atomic Structure and the Periodic Table

This unit covers the structure of the atom, isotopes and relative atomic mass, electronic structure, the development of the periodic table, and the properties of Group 1, Group 7 and Group 0 elements. Triple students also study transition metals.

Learn the subatomic particles with their relative masses and charges first — almost every later calculation depends on them. Electronic structure follows directly, and the ability to write a configuration such as 2,8,1 explains why an element sits where it does. Group trends are the most examined part of the unit, and answers need explaining rather than stating: reactivity increases down Group 1 because the outer electron is further from the nucleus and more easily lost. Students most often lose marks by describing isotopes as having different numbers of protons, and by giving trends without reasons.