1. The Chemical Basis of Life

2. Objectives:
Explain the relationship between elements, compounds, atoms, and molecules
List the major elements and major minerals
Discuss atomic structure and explain how an atom’s electron shells influence its ability to enter into chemical reactions

3. Objectives
Compare and Contrast the three major types of chemical bonds
List and describe the three basic types of chemical reactions that occur in living material

4. Terms Biochemistry- chemistry that deals with living organisms
Matter- anything that occupies space and has mass
Elements- can’t be broken down into tow or more different substances
EX: O2

5. Terms Compound- two or more elements together EX: CO2 or NaCl
Major elements- make up a large portion of our body
Trace elements- are present in the body in small amounts

6. Chemical Symbols O- oxygen C- carbon H- Hydrogen N- Nitrogen
Ca- Calcium
P- Phosphorus
K- Potassium
S- Sulfur
Na- Sodium
Cl- Clorine
Fe- Iron
I- Iodine

7. Atoms basic building block of all things
can be broken down into subatomic particles

8. Atomic Structure Protons positive found in the nucleus Neutrons
neutral

9. Atomic Structure
Electrons
negative
found in the electron shell

10. Atomic Number and Weight
Atomic number- the number of protons in a nucleus
Atomic weight- mass of an atom
only the nucleus has weight
equals the number of protons and neutrons

11. Electron Shells The number of electrons equals the number of protons
use the Bohr model to visualize electrons

12. Bohr Model Each ring is different energy level First shell holds two
Second shell holds 8
If outer shell is full, the atom won’t form bonds

13. Bohr Model
Rule of Octet- says the outer shell can hold eight electrons

14. Isotopes All atoms of the same element have the same number of protons
They do not contain the same number of neutrons and these are called isotopes
Ex: Most carbon has 6 electrons but carbon 14 has 8
atomic weight of 14

15. Chemical Bonds Molecule- any two or more atoms coming together
Compound- two or more different atoms come together
NaCl

16. Ionic or Electrovalent Bonds
Forms by the transfer of electrons
occurs as a result of electrically charged atoms called ions

17. Ionic Bonds
Na needs to lose one, Cl needs to gain one

19. Covalent Bonds
Shares Electrons

21. Hydrogen Bond Form due to unequal charge
no electrons are shared or transferred
Water is a hydrogen bond
Are very weak
Allows water to change states

22. Chemical Reactions Synthesis- putting things together A + B = AB
Decomposition- take things apart
AB= A + B
Exchange
AB + CD = AC + BD