1. Chapter 2, Section 2
Combinations of Atoms

2. Interactions of Atoms Compounds
Atoms of more than one type of element that have been chemically bonded together
Often have different properties than the elements that formed them

3. Interactions of Atoms Chemical Formulas
Show the ratios and types of atoms in a compound
NaCl
H20
HCl

4. Interactions of Atoms Chemical Properties
Describe changes that occur when one substance reacts with another substance

5. Bonding Chemical Bond Force that holds atoms together in a compound
Form when atoms share or exchange electrons in their outermost energy level
Outer energy level is considered stable (and won’t form bonds) when it has 8 electrons
Chemical Bond

6. Bonding Covalent Bonds
Form when atoms share the electrons in their outermost energy levels

7. Bonding
Molecule
Group of atoms connected by covalent bonds

8. Bonding
Ionic Bonds
Form when oppositely charged ions join together to form a neutral compound

9. Bonding Metallic Bonds Occur in metals
Electrons are free to move from one positively charged ion to another
Results in conductivity

10. Bonding Polar Molecules
Molecules with slight positive and negative charges due to unequal sharing of electrons
Example: Water

11. Bonding Hydrogen Bonds
Weak bonds formed between the negative end of one water molecule and the positive end of another water molecule

12. Mixtures
Mixture
Two or more substances that are not chemically combined

13. Mixtures Heterogeneous Mixtures Not mixed evenly
Each component retains its own properties

14. Mixtures Homogeneous Mixtures Evenly mixed
Properties of the components are often different from the properties of the mixture
Often called a solution

15. Separating Mixtures and Compounds
Mixtures vs. Compounds
Mixtures can be separated by physical means
Compounds must be separated by chemical means