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Ionic and Covalent Bonds
How Elements Form Compounds
Two or more elements chemically combined.
Compound
called an ionic compound because it is made up of negative and positive ions that have resulted from the transfer of electrons from a metal to a non-metal.
Ionic Compounds
Ions in ionic compounds are held together by the electrostatic force between oppositely charged bodies. In other words, positive and negative ions attract.
Ionic Compounds
For example:
Sodium (Na) wants to lose ____ electron). Chlorine (Cl) wants to gain ____ electron).
Ionic Compounds
Ionic Compounds
Ionic Compounds
Calcium needs to lose ____ electrons, and fluorine needs to gain ____
Calcium Fluoride
What happens?
Calcium Fluoride
What happens?
Calcium Fluoride
In the chemical formula the symbols of elements are written with a subscript which indicates how many of that element are present in the compound
only numbers above one are written
Chemical Formulas and Composition of Compounds
Formula for sodium chloride =
Formula for calcium fluoride =
Chemical Formulas and Composition of Compounds
NaCl
CaF2
Ionic compounds are called electrolytes.
Electrolytes are substances that when dissolved in water, conduct electricity.
Electrolytes
form when non-metals combine with non-metals
non-electrolytes because they form solutions that do NOT conduct electricity.
Covalent/Molecular Compounds
Valence electrons are shared between atoms to fill the outer shell
Covalent/Molecular Compounds
pg. 191 #1, 2 (Lewis diagram instead), 3, 4, 6, 7
pg. 195 #1, 2, 6, 7, 9
Homework