The Matter — Structure of the Atom

About this lesson

This unit introduces the structure of the atom as the building unit of matter. It covers the discovery of the atom's structure, focusing on Ernest Rutherford's experimental model. Students learn about the subatomic particles (protons, neutrons, and electrons), their charges and masses, and the concept of the nucleus. The text explains energy levels, how electrons are arranged in them (including the 2n² rule and the 8-electron outer shell limit), and the symbols used for chemical elements. It also discusses the relationship between the number of protons, neutrons, and electrons in an atom, leading to the definitions of atomic number (Z) and mass number (A), and introduces isotopes as atoms of the same element with different numbers of neutrons. Activities and evaluation questions reinforce these concepts, including identifying isotopes and determining atomic structure from given data.