1. BASIC CHEMISTRY Matter: anything that occupies space
Elements: substances that cannot be broken down chemically into simpler parts (Ex. Hydrogen, oxygen, carbon, iron)
Over 100 have been identified in nature
Less than 30 are important to living things
Atom: the simplest particle of an element that retains all of the properties of that element
The basic building blocks of all matter

2. Atoms
Nucleus
Subatomic particles
Protons (+ charge)
Neutrons (0 charge)
Atomic Number: the number of protons in the nucleus of an atom
Mass Number: the mass of both the protons and the neutrons in the nucleus of an atom
All atoms of the same element have the same number of protons

3. Isotopes
All atoms of an element do not have the same number of neutrons
Isotopes: atoms of the same element that have a different number of neutrons

4. Electrons
Electron: negatively charged, energetic particles orbiting the nucleus of an atom
The number of protons = the number of electrons
Outside electrons have more energy and are responsible for bonding atoms to each other to form COMPOUNDS

5. Compounds
Compound: 2 or more atoms or elements bonded together in fixed proportions
Chemical formula: shows the proportions of each element
Examples:
H₂O = water (2 hydrogen, 1 oxygen)
O₂ = oxygen gas
C₂O = Carbon Dioxide

6. Chemical Bonds Most elements are not stable in nature
They want to have a balanced number of electrons in their orbit to become stable
Molecule: the simplest part of a substance that retains all of the properties of that substance and can exist in a free state

7. Bonding Chemical Bonds: the attractive forces that hold atoms together
Covalent Bond: when 2 atoms share one or more electrons
Example: water H₂O

8. Bonding
Ionic bond: bonding of 2 atoms because of the electrical attraction to each other
+ and – charges attract
Ex. Sodium has a positive charge and Chlorine has a negative charge = sodium chloride (table salt)

9. Energy and Matter Energy: the ability to do work
Energy can be converted into various forms
Law of conservation of energy: energy cannot be created or destroyed, it can only be transferred from one form to another

10. States of Matter All atoms are in constant motion
Spacing and movement of atoms determine the state of matter of the substance
THERMAL Energy must be added or taken away for a matter to change state

11. States of Matter Solid Liquid Gas
Atoms are tightly packed
Little movement
Maintains a fixed volume and shape
Liquid
Has a fixed volume
Atoms move more freely than in a solid
Can flow and conform to different shapes
Gas
Atoms have little or no attraction to each other
Atoms fill the space they occupy
**Water is the only exception to this rule**

12. Energy and Chemical Reactions
Chemical Reaction: One or more substances changes to produce one or more different substances
Energy is absorbed when bonds are created
Energy is released when bonds are broken
PRODUCTS
REACTANTS

13. Chemical Reactions
Metabolism: all of the chemical reactions that occur in an organism to maintain its internal function and create energy
Breaking down food
Making new cells and DNA
Growing
Making hormones
Circulating blood