1. Atoms and Their Interactions
6.1

2. Elements
Elements
A substance that can not be broken down into simpler chemical substances
The Periodic Table lists all known elements

3. Atoms: The Building Blocks of Elements
Smallest particle of an element that has the characteristics of that element
Structure of an Atom
Nucleus
Protons (Positive)
Neutrons (Neutral)
Energy levels
(outside of the nucleus)
Electrons (Negative)

4. How come atoms do NOT have a charge?
In an atom, the number of electrons equals the number of protons.
So the number of positive and negative charges balance out, giving the atom a charge of 0.

5. Fill in the following chart:
Particle
Location
Charge
Symbol
Electron
outside of nucleus
In energy levels
negative e-
Proton
Inside the nucleus
positive p+
Neutron
neutral n0

6. Energy Levels First energy level Second energy level
2 electrons
Second energy level
8 electrons
Third energy level
18 electrons
Rules for filling in energy levels!
The first energy level has to be FULL before electrons can go into the 2nd energy level
The 1st and the 2nd energy level has to be FULL before electrons can go into the 3rd energy level

7. Compounds
Compounds are substances made of 2 or more elements that form a molecule (2 or more atoms together).
Examples of common compounds:
Table Salt - NaCl
Oxygen gas – O2
Water – H2O

8. Properties of Compounds
Compounds have BONDS between the atoms
It is difficult to separate the parts of a compound
Compounds have chemical formulas to tell you what elements are found in the compound and how many atoms of each element are present.
The chemical formula for water is H2O. There are two atoms of hydrogen and one of oxygen.

9. Ionic Vs. Covalent Bonds
Ionic Bonds
Form when electrons are exchanged between atoms.
Covalent Bonds
Form when electrons are shared between atoms.
Both types of bonds result in all atoms having a full outer energy level.

10. Chemical Reactions
Chemical reactions happen when bonds are formed or broken and recombine to form new compounds
All chemical reactions that occur within an organism are referred to as that organism’s metabolism.

11. Mixtures
Mixtures are combinations of 2 or more pure substances or compounds
Some common mixtures:
Iced Tea
Dirt
Paint

12. Properties of Mixtures
There are NO BONDS holding mixtures together
Mixtures can often be separated
Mixtures can occur in any proportions and DO NOT HAVE A SET FORMULA and can use different components

13. Solutions
Solution – mixture of one or more substances uniformly distributed in another substance.
Can be solid, liquid, gas
ex. Plasma (liquid)
brass (solid) copper and zinc
soda (liquid/gas) water and CO2

14. Acids & Bases
The Homeostasis of living things depends on the degree of acidity (acid) and alkalinity (base) in certain areas

15. Acids & Bases Acids= any substance that forms hydrogen (H+) in water.
Alkalinity (a/k/a basic solution)= any substance that forms hydroxide ions (OH-) in water

16. Acids - pH < 7 Sour taste Corrosive on metals Burns skin
Ex. Orange juice,
vinegar, sulfuric acid
*Homeostasis relevance
- your stomach must have a certain acidity to function properly

17. Bases Tastes bitter Slippery Irritate the skin Ex. NaOH
-pH > 7
Tastes bitter
Slippery
Irritate the skin
Ex. NaOH
Homeostasis relevance-
your small intestine needs a certain alkalinity (basic) to function properly

18. pH Scale Tells you how acidic or basic something is Ranges 0-14
7 = neutral
above 7 = base
below 7 = acid
Ten fold system
Measure pH with litmus paper