1. The Chemistry of Life

2. Atoms and Their Interactions
We will start by looking at the elements…

3. Elements are made up of particles called atoms
An atom is the smallest particle of an element that has the characteristics of that element.

4. Protons Neutrons electons
1. Name the 3 subatomic particle, their location within an atom, and their charge
Protons
Neutrons
electons

5. Protons, p+ +1 charge Very small Found in the nucleus
# of p+ in an atom determines what it is
Proton

6. Neutrons, no Have no charge Same mass as a proton
Very small
Also found in the nucleus
Neutrons

7. Electrons, e- Outside of the nucleus are the electrons, e-: -1 charge
Even smaller that p+ and no
Located very far away from the nucleus in a region called the orbitals or energy levels
There is a lot of space between the nucleus and electrons

8. Parts of the Atom From the inside to the outside:
The center of the atom is the nucleus
The nucleus contains
Protons
Neutrons

9. a. give the # of p, n, e b. example: atomic #9 Atomic Mass = 19
2. When given the atomic #, atomic mass, or symbol for an atom, be able to:
a. give the # of p, n, e
b. example: atomic #9
Atomic Mass = 19
# of protons = 9
# of Neutrons = 10
# of electrons = 9
Symbol = F (fluorine)

10. The Periodic Table (Pages 36 & 37 of your book)1
Atomic Number H
Element
Symbol
Element
Name
Hydrogen
Mass
Number or
Atomic
1.0079

11. Periodic Table Lab Activity
Put lab into your table of contents.
Get started finding all elements listed.

12. On Earth, 90 elements occur naturally
Element - subst. that can’t be broken down into simpler chemical substances
Represented by a symbol
Ex.) C represents Carbon, Ca represents Calcium
On Earth, 90 elements occur naturally
Only about 25 are essential to living organisms
Four elements make up more than 96% of the human body
Hydrogen, Oxygen, Nitrogen, & Carbon

14. So where do all these parts of an Atom Go??

15. 3. If an atom has 12 electrons, how many are in it’s outer level?
Find element 12 on periodic table:

16. 4. How many electrons, maximum, can fit into the 1st, 2nd, and 3rd energy levels of an atom?

17. The K-shell Can hold 2 electrons
Hydrogen (1 proton, 1 electron)
Helium (2 protons, 2 electrons)

18. The L-shell Can hold 8 electrons
                                   Lithium
                                   Beryllium
                                   Boron
                                   Carbon
                                   Nitrogen
                                   Oxygen
                                   Fluorine
                                   Neon

19. The M-shell Can hold 8 electrons
Potassium
Calcium

20. An element is stable when it has a full outer shell of electrons.
5. Determine if an atom is stable, based on how many electrons are in its outer level.
An element is stable when it has a full outer shell of electrons.
It must have a shell of 2 then 8 electrons.
An element with a full outer shell (8) will be stable and act like its nearest noble gas.

21. Atomic Structure Practice
Now practice drawing the following Atomic Structures:
Make sure to cut out and tape into lab book.

22. - Compounds and Bonds notes
6. If an atom has 8 electrons, how many covalent bonds will it likely form? 7. Describe the behavior of electrons in a covalent, polar covalent and ionic bond.
- Compounds and Bonds notes

23. Compounds & Bonding
A Compound is a substance composed of 2 or more elements bonded together
Ionic Bond - attractive force between 2 ions of opposite charges (“opposites attract”)
Covalent Bond - 2 atoms share electrons
More abundant in living things!!

24. 8. If an atom gains 2 electrons, what is it’s charge. 9
8. If an atom gains 2 electrons, what is it’s charge? If an atom loses 1 electron, what is it’s charge?

25. 10. If two atoms are isotopes, what is the difference between them?
If the # of e- changes, then it is called an ion
If the # of no changes, then the atom is called an isotope

26. Atomic Structure and Bonds
STOP
Atomic Structure and Bonds
Activity sheet handout

27. 11. What are the 6 most common elements found in living things?
Oxygen (O)
Carbon (C)
Hydrogen (H)
Nitrogen (N)
Phosphorus (P)
Sulfur (S)

28. 12. What are trace elements and give an example of why they are important.
Elements that make up less than 0.01 percent of your body mass, but are critical to your health.
Example: You need about 0.15mg of the trace element Iodine each day.

29. 13. Explain why water is a polar molecule.
Water is a polar molecule because it’s opposite ends have opposite charges.
Sketch and label a water molecule:

30. 14. If given one water molecule, be able to sketch 3 additional water molecules.
Draw this:

31. STOP
How do we know all this?
Indirect evidence: gathering info about something you can’t see through experiments
Ex.) guessing what is inside the box
Based upon indirect evidence, models of the atom have been created, tested, and improved.

32. Chemical reactions can either break or form new bonds between compounds
All of the chemical reactions that occur within an organism are referred to as the organism’s metabolism

33. Mixtures
A combination of 2 or more things that are not chemically combined.
Easy to separate based on physical properties

34. 15. What values on the pH scale are acidic, basic, neutral?

35. Acids & Bases Acids and bases are important to living systems Acids
pH < 7 and forms hydrogen (H+) ions in water
Bases
pH > 7 and forms hydroxide (OH-) ions in water

36. 16. Does an acid have more or less hydrogen ions (H+) than hydroxide ions (OH-)? Base? Neutral?
Acid = more H+
(H+) > (OH-)
Base = more OH-
(H+) < (OH-)
Neutral = equal
(H+) = (OH-)

37. 17. Is something with a pH of 3 more or less acidic than something with a pH of 4?
MORE Acidic

38. 18. Describe what happens when acids or bases are added to a buffer solution.
Buffer solutions are used as a means of keeping pH at a nearly constant value.
Many life forms thrive only in a relatively small pH range so they utilize a buffer solution to maintain a constant pH.

39. 19. Name one place in your body that you could find a buffer and why it’s important.
One example of a buffer solution found in nature is blood.
Important so that our bodies can probably use nutrients from the different foods/liquids we eat/drink everyday.

40. 20. Describe 5 properties of water that are important to life.
Cohesion and Adhesion:
Temperature Moderation
Low density of Ice
Ability to dissolve other substances
Buffering of pH (acids and bases)
- Use book or online to find out WHY for each answer above…(homework).