1. Chemistry of Biology

2. Protons, Neutrons, and Electrons
In a neutral atom, protons and electrons are always equal
Atomic Number identifies the number of protons in a specific element
Change in atomic number/protons means a change in elements
Atomic mass is the total number of protons plus neutrons

3. Ions and Isotopes
An ion is defined as an electrically charged atom or group of atoms
An ion is created by the addition or subtraction of electrons
Two types of Ions:
Cations: positively charged ion resulted by the loss of electrons
Anion: negatively charged ion resulted by the gaining of electrons
Isotopes are atoms of the same element that differ in the number of neutrons (protons stay the same)
Ex) Carbon-12, Carbon-13, Carbon-14

4. Elements vs. Compounds
Elements: substance consisting entirely of one type of atom
Compound: substance formed by the chemical combination of two or more elements in definite proportion
Mixture: material composed of two or more elements or compounds that are physically mixed together but not chemically combined

5. Ionic vs. Covalent Bonds
Ionic bond is the transferring of electrons when two or more atoms chemically combine
Covalent is the sharing of electrons when two or more atoms chemically combine

6. Solutions
Solution: mixture of two or more substances in which the molecules of the substances are evenly distributed
Two parts to a solution
1) Solute: substance that is dissolved in a solvent to make a solution (salt)
2) Solvent: substance in which a solute is dissolved to form a solution (water)
Solution=salt water

7. Properties of Water Water is a polar molecule
Uneven distribution of electrons between the oxygen and hydrogen atoms
Cohesion: attraction between molecules of the same substance
Water molecules attraction to one another
Adhesion: attraction between molecules of different substances
Water molecules attraction to a countertop or other surface

8. pH pH is the measure of how acidic or basic a solution is
Acids: any compound that forms H+ ions
Base: any compound that forms OH- ions
pH scale: measurement system to determine the concentration of H+
Ranges from 0-14
acid; 7 neutral, base