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