1. It’s All Elementary: Chemistry Basics

2. The teeny, tiny stuff:
Atom: Smallest particle of an element that retains the characteristics of that element.
Element: The pure chemical substance containing only one type of atom
Compound: A combination of elements, chemically bonded

3. Essential Elements
An element is a pure substance that contains only one type of atom.
Examples: H – hydrogen
C – carbon
O – oxygen
Elements are usually found combined with other elements as compounds.
Compound – a substance formed when two or more elements are chemically bonded.
Example – C6H12O6 - Sugar

4. Structure of an atom: The basic unit of matter is the atom.
Atoms have three basic parts:
Protons (+ charge)
Neutrons (no charge)
Electrons (- charge)
These are the tiniest and weigh practically nothing.

5. The Bohr Atom Model
The Bohr model is used to visually depict the structure of an atom.
Protons and neutrons are located in the nucleus.
Electrons are in constant motion in the space around the nucleus.

6. Periodic Table Crash Course
A table of elements, arranged by atomic number
Metals are left of the zigzag, Nonmetals to the right (except H)
Elements are uncharged, which means the number of protons MUST EQUAL the number of electrons
Column numbers tell you valence shell electron number and how they might bond
Valence shell electrons: The outermost electrons on an atom.
Hydrogen: 1 valence e-
Oxygen: 6 valence e-
Carbon: 4 valence e-

7. Bonding – it doesn’t always require glue.
There are three basic types of chemical bonds:
1) Ionic – formed when electrons are transferred from one atom to another.
This type of bond creates ions.

8. Bonding……
2) Covalent – formed when electrons are shared between atoms.
This type of bond creates molecules.
3) Van der Waals Forces – a slight attraction between oppositely charged molecules.

9. Copyright Pearson Prentice Hall
One more bond type…Van der Waals Forces
When molecules are close together, a slight attraction can develop between the oppositely charged regions of nearby molecules.
Copyright Pearson Prentice Hall

10. Demo of covalent bonding

11. Writing chemical bonds:
Molecules can be illustrated in 3 different ways:
1) Chemical formulas – subscripts are used to indicate the number of each type of atom
H2O, CH4, CO2
2) Structural formulas - lines are drawn between element symbols to indicate bonds

12. 3) Molecular model – 3D model of what the molecule looks like

13. Compounds are NOT Mixtures
Mixture: A combination of substances where both keep their original properties.
Physically mixed, not chemically mixed.
Solution: One or more substances (solutes) are distributed evenly in another substance (solvent)
The more solute in a solvent, the higher the concentration.
Suspensions: Mixtures of water and non dissolved particles
Example: Blood

14. pH Scale
pH: a measure of how acidic or basic something is (pH: power of Hydrogen)
pH 0-6: Acid
Acids form H+ ions in water
Example: Lemon (pH=2)‏
pH 7: Neutral
Example: Pure water and blood‏
pH 8-14: Base
Bases form OH- ions in water
Example: Ammonia (pH=12)‏
Buffers: Solutions that prevent sudden changes in pH.