Chapter 1. The Storyline

1.1 The Storyline

How are atoms connected with one another?

All of the objects in our everyday world, including ourselves, are made up of large numbers of atoms. But what holds those atoms together? Why don’t objects just crumble into piles of individual atoms? Why is the desk in your classroom solid, while water simply runs through your fingers? Something about the way atoms are connected must give substances the properties we observe.

Storyline: Objects in the Everyday World
  • Brief reading to provide connections and rationale.
  • Should be centered around a picture or image.
  • Think about it (no need to look things up or have prior knowledge specific to the lesson)

1.2 The Storyline

Electrons (negatively charged particles) are attracted to the positively charged nucleus of an atom. While the core electrons remain close to nuclei of individual atoms, the valence electrons can be attracted by and shared with two or more atoms. It is these attractions between the nucleus of one atom and the valence electrons of another atom that account for bonds that hold atoms together in molecules. Four types of bonds (ionic, covalent network, molecular covalent, and metallic) exist representing different distributions of valence electrons. With this understanding, it is possible to explain and predict properties of substances.

Storyline: Covalent Sharing

Key Idea: Valence electrons are located so as to bond or "glue" the positively charged atom cores together.

  • Brief reading to provide connections and rationale.
  • Should be centered around a picture or image.
  • Think about it (no need to look things up or have prior knowledge specific to the lesson)