I. Bonding

A. Compounds consist of atoms of two or more elements that are joined by chemical bonds

B. Types of Bonds1. A covalent bond is formed

when two atoms share electrons.

Chapter 2

2. An ionic bond is formed when one atom gives up an electron to another. The positive ion is then attracted to a negative ion to form the ionic bond.

Remember…..Chemical Reaction

1. reactant + reactant productsbefore change after

change

Bell work

Explain how a covalent bond is formed and then explain how an ionic bond is formed.

B. Law of Conservation of Mass

• MASS IS NEVER CREATED OR DESTROYED!1. Balancing chemical equations helps the # of

reactant atoms = # of product atoms. (Reactions keep all the atoms and rearrange

them!)

How do you count atoms?

CO₂ = 1 carbon and 2 oxygen atoms2CO ₂ = 2 Carbon and 4 oxygen atomsCa(OH) ₂= I calcium, two oxygen, and two

hydrogen atoms2Ca(OH) ₂= 2 calcium, 4 oxygen, and 4 hydrogen

atoms

How about this hard one!

• 3 Al ₂(CO₃) ₃ –How many Aluminum?

3 x 2 = 6 aluminum atoms-How many carbon atoms3 x1 x 3 = 9 carbon atoms-How many oxygen atoms?3 x3 x3 = 27 oxygen atoms

Now that you can count the atoms are they even on both sides of the reaction?

_____ H₂ +_____ O ₂ _____ H ₂O

b. 3O ₂ ___O₃

c. ____ NO(g) ____ N₂O(g) + ____NO ₂

K+

NO -3

A carbon gives away an electron

Oxygen gains an electron

O-2 gains two electrons