2. Chemistry Notes outline
Elements
found in humans=
organic=
Atom structure
A. nucleus (protons,
neutrons)
B. Electrons (levels,
valence)
Mass vs. Atomic #
Table
Compounds
a. Ionic bonds
b. Covalent bonds
VI. Orbital drawings

3. Why study chemistry in biology class?
We need to know the makeup of living things before trying to understand them
Chemical reactions are always occurring in the body

4. Section 6.1 Summary – pages 141-151
Elements
All things (living and nonliving) – whether it is a rock, frog, or flower – are made of substances called elements.
Element—a substance that can’t be broken down into simpler chemical substances.
Section 6.1 Summary – pages

5. Elements Examples—gold, carbon, hydrogen, oxygen, and nitrogen.
If pure gold is ground into pieces, it is still gold.

6. Elements
Humans contain: C, H, O, N which makes up > 96% of our bodies
All living things contain carbon = organic!!

7. Section 6.1 Summary – pages 141-151
Atoms: The Building Blocks of Elements
All elements are made up of atoms.
Atom—the smallest particle of an element that has the characteristics of that element.

8. The structure of an atom
Nucleus—the center of an atom
Proton—positively charged particles inside the nucleus
Neutrons—Neutral (no charge) particles inside the nucleus
Protons
Neutrons
Nucleus

9. Section 6.1 Summary – pages 141-151
Electron energy levels
Nucleus
8 protons (p+)
8 neutrons (n0)
Electrons—extremely small particles with negative charge located in electron cloud
Oxygen atom
1st energy level—maximum 2 electrons
2nd energy level—maximum 8 electrons
3rd energy level—maximum 18 electrons
Section 6.1 Summary – pages

10. The Structure of an atom
Valence electrons: electrons in outer energy level
Atoms contain—equal numbers of protons and electrons so they have no charge

11. Periodic Table of Elements—Displays the elements and their symbols
Atomic mass = weight of nucleus (protons and neutrons); big number on periodic table
Atomic number = # protons = # electrons; little number on periodic table

12. In summary Type of particle Location Charge Symbol How many? Proton
nucleus
positive P+
Atomic #
Neutron
Nucleus
Neutral n°
Atomic mass - #
Electron
Energy levels
Negative E-

13. Compounds Compounds—A substance made up of atoms of 2 or more elements
Water molecule
2 hydrogen atoms
1 oxygen atom

14. Chemical bonds Atoms are stable when outermost energy level is full
In order to become stable atoms with either gain/lose or share electrons
Ionic bond: electrons transferred from one atom to another
Covalent bond: atoms share electrons
Very strong bond

15. Orbital drawings—diagram of an atom with its electrons arranged around the nucleus
# of protons— 7
# of neutrons— 7
# of electrons— 7

16. Make an orbital drawing for fluorine (F)-- Fill in the #’s of protons and neutrons, all of the electrons, and label the nucleus and energy levels.
# of protons—
# of neutrons—
# of electrons—

17. Let’s Practice
We’ll draw chlorine (17, 35) and sodium (11, 23) bonding:

18. Who wants to draw on the board?
Beryllium

19. Another volunteer?
Argon

20. One more
Aluminum