Making Molecules (aka…combining capacity)

Atoms combine to form molecules based on the electrons in their outer shell. We saw from Bohr Diagrams that H, Li, Na, and K all have 1 electron in their outer shell. Therefore, they have a combining capacity of 1. Be, Mg and Ca all have 2 electrons in their outer shell. They all have a combining capacity of 2. Rules for combining elements - Table 1 pg 42 1.Metals combine with nonmetals 2.Write the name of the metal first and the nonmetal second 3.Change the ending of the nonmetal to “ide” 4.Each atom has its own combining capacity 5.Atoms combine so that each can fill its combining capacity

Examples: Lithium and fluorine LiF Or… Li - F Formula : LiF Name : Lithium fluoride 1 1

Examples: Magnesium and chlorine Cl Or… Cl – Mg - Cl Formula : MgCl 2 Name : Magnesium chloride Mg 2 1

Examples: Calcium and phosphorus Or… Formula : Ca 3 P 2 Name : Calcium phosphide Ca P P Ca P Ca 2 3