1. The Chemistry of Life
Chapter 2

2. The Chemistry of Life
Before we can talk about biology, we need to discuss Chemistry
The atom is the most basic unit of matter
All atoms are made up of three parts:
Protons (nucleus)—Positive
Electrons—Negative
Neutrons (nucleus)—Neutral

3. Atoms
Because protons are positive, the nucleus is positive; BUT the electrons (negative) cancel out the charge
Each element’s atomic number is the same as the number of protons
Each element’s atomic mass is the total number of protons and neutrons

4. Practice
What is the atomic mass of Carbon if Carbon has 6 protons and 6 neutrons?
What is the atomic number of Oxygen if Oxygen has 8 electrons?
What is the atomic mass and number of Magnesium if Magnesium has 12 electrons and 12 neutrons?

5. Ions & Isotopes
Some atoms can lose or gain electrons, making the atom positively or negatively charged. These atoms are called ions
Some atoms of the same element have different numbers of neutrons, giving them different weights. These atoms are called isotopes

6. Chemical Compounds
A chemical compound is a substance made up of two or more elements
H2O
CO2
NaCl
The chemical formula tells what and how much is in the compound

7. Chemical Bonds 2 kinds of chemical bonds: Ionic Bonds
Formed between ions (atoms that have lost or gained electrons)
One atom gives electrons to the other
Covalent Bonds
Electrons are shared between atoms

8. Chemical Bond EXamples
Covalent Bond
Ionic Bond

9. Properties of Water Using the Bio Book, define the following terms:
Cohesion
Adhesion
Mixture
Solution
Solute
Solvent
Suspension
pH Scale
Acid
Base
Buffer

10. Properties of Water Cohesion—when water molecules stick to each other
Adhesion—when water molecules stick to a surface
Surface Tension—force in the surface of a liquid that causes the layer to behave like an elastic sheet
Solvent—liquid that dissolves other substances