1. Chem-To-Go Lesson 13 Unit 4 IONIC BONDING - WRITING FORMULAS Need a periodic table!

2.  Most neutral atoms are unstable.  In order to become stable, most atoms need achieve 8 valence electrons.  Metals lose electrons to become stable.  Many nonmetals gain electrons to become stable.  Many nonmetals share electrons to become stable.  Part 1: Ionic Bonding  Metals bonding to nonmetals  Involves losing electrons & gaining electrons [ions]  Part 2: Covalent Bonding  Nonmetals bonding to nonmetals  Involves sharing valence electrons [no ions] QUICK OVERVIEW

3.  A sodium atom loses an electron to become stable. The atom becomes a +1 ion.  A chlorine atom gains the electron to become stable. The atom becomes a -1 ion.  Opposites attract. The Na +1 and Cl -1 are bonded by a force of attraction.  Notice that the overall charge of the compound is neutral. IONIC BONDING

4.  Metal: Magnesium  Nonmetal: Nitrogen MORE COMPLEX EXAMPLE A simple 1 to 1 ratio of atoms doesn’t address the needs of each atom.

5. EXAMPLE: calcium and phosphorus CRISS-CROSS FORMULA WRITING NOTICE: THE FINAL FORMULA IS NEUTRAL.

6. EXAMPLE: aluminum and sulfate ion CRISS-CROSS FORMULA WRITING NOTICE: THE FINAL FORMULA IS NEUTRAL.

7. EXAMPLE: tin(II) and carbonate ion CRISS-CROSS FORMULA WRITING NOTICE: THE FINAL FORMULA IS NEUTRAL.

8. EXAMPLE: Sodium hypochlorite WRITING FORMULAS FROM NAMES

9. EXAMPLE: magnesium phosphate WRITING FORMULAS FROM NAMES

10.  All final formulas are neutral.  No superscripts or charges appear in the final formula.  Always and only reduce subscripts in the final answer, but never change a polyatomic ion.  Use parentheses around polyatomic ions when a subscript is needed. SUMMARY