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Ionic bonding - writing formulas. Chem -To-Go Lesson 13 Unit 4. Quick overview. 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.
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Ionic bonding - writing formulas Chem-To-Go Lesson 13 Unit 4
Quick overview • 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]
Ionic bonding • 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.
More Complex example • Metal: Magnesium • Nonmetal: Nitrogen A simple 1 to 1 ratio of atoms doesn’t address the needs of each atom.
Criss-Cross Formula Writing EXAMPLE: calcium and phosphorus NOTICE: THE FINAL FORMULA IS NEUTRAL.
Criss-Cross Formula Writing EXAMPLE: aluminum and sulfate ion NOTICE: THE FINAL FORMULA IS NEUTRAL.
Criss-Cross Formula Writing EXAMPLE: tin(II) and carbonate ion NOTICE: THE FINAL FORMULA IS NEUTRAL.
Writing formulas from names EXAMPLE: Sodium hypochlorite
Writing formulas from names EXAMPLE: magnesium phosphate
Summary • 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.