1. Chapter 2-2
Combinations of Atoms

2. How atoms combine Atoms combine in two ways;
When atoms combine they lose their chemical properties and take on new ones.
1. Sharing electrons in outer energy levels
Molecules – smallest part of a compound made by sharing electrons
Compound – 2 or more elements chemically combined
H2O – is a molecule

3. Water Molecule

4. Ions – positive or negative charged atom
2. Gaining or losing electrons in outer energy levels
Losing electrons - positive charge atom
Gaining electrons – negative charge atom
Ions – positive or negative charged atom
Ions are attracted by the unlike charges
NaCl – table salt is an ionic compound

5. Salt Na – sodium - one electron in outer energy level - loses electron
- positive ion
Cl – chlorine
- 7 electrons in outer energy level
-gain electron
- negative ion

6. Aluminum oxide Al2O3 Al loses 3 e = + ion O gains 2 e = - ion
Takes on all new properties.

7. Mixture
Mixture – combination of 2 or more compounds but each retains its own properties
Can easily be separated
Lucky Charms - example of mixture
Marshmallows oat cereal

8. Solution Solution – one substance is dissolved into another substance
Each substance retains its properties yet they appear as one substance.
The distribution of the substances are the same throughout the solution.
Can be separated

9. Parts of a solution Solute: part being dissolved
Solvent: part doing the dissolving
Dissolving: moving of solute between particles of solvent
Bipolarity of water helps it to dissolve

10. Compounds Difficult to separate Must use chemical means
Chemical change – converting one substance into its elements.
C6H12O6

11. States of Matter

12. Solid Atoms strongly attracted Tightly packed
Vibrate very slowly to and fro
Definite shape and volume

13. Liquid Particles further away Attraction weaker Move over and around
No definite shape/take shape of container
Definite volume

14. Gases Attraction minimal Movement – fast No definite shape
No definite volume
Fill entire container place into

15. Plasma – 4th state of matter
Plasma – gaseous state made of free flowing ions and electrons
Lightning
Fluorescent bulb
Stars
Sun

17. Changing states of matter
Energy is added or removed
Adding energy = solid to liquid to gas
Removing energy – gas to liquid to solid
Freezing pt. – l to s
Boiling pt – l to g

18. Changing States of Matter