1. The Chemical Level of Organization
Atoms
Atomic Structure
Electron Shells, losing/gaining electrons
Ions
Molecules, their formation through bonds
Chemical Bonds (how, why, and types)
Macromolecules
4 major macromolecules

2. Elements & Atoms

3. Elements
Different kinds of matter (material) that have distinct (chemical) properties
Examples:
gold
carbon
hydrogen
sodium
nitrogen
calcium
oxygen

7. many different object/pictures
5 basic shapes

8. Atoms
Smallest unit/piece of an element (matter) that still has the properties of that element.
TAKE A BAR OF GOLD/IRON AND BREAK IT UP INTO THE SMALLEST BIT THAT IS STILL IRON/GOLD THAT WOULD BE AN ATOM
WRITE THE 3 PARTICLES AND 2 REGIONS ON THE BOARD

9. The structure and components of an atom
--Neutral
--positive
--negative
EXPLAIN AND WRITE ABOUT ELECTRON SHELLS
SHOW HOW MANY THE FIRST 4 HOLD
EXPLAIN VALANCE SHELLS--OUTERMOST

10. Electron Shell (orbital)
Proton
Neutron
Electron
Electron Shell (orbital)
Nucleus

11. Different elements are made of atoms with different numbers of protons and electrons—that is why each element has its own unique set of properties
2p, 2e, Helium
4p, 4e, Beryllium
3p, 3e, Lithium

12. Element
Number of protons
Number of electrons
% of Body
by Weight
Hydrogen 1
9.5
Carbon 6
18.5
Nitrogen 7
3.3
Oxygen 8
65.0
Sodium 11
0.2
Sulfur 16
0.3
Chlorine 17

13. Valence Shells outermost shell of atom = valance shell
Atoms are most stable when the outer shell is filled, or emptied.
Valance shells

14. Electron shells of common elements Valance in red
1st shell
2nd shell
3rd shell
4th shell
Hydrogen 1
Carbon 2 4
Nitrogen 5
Oxygen 6
Sodium 8
Chlorine 7
Potassium
calcium
TALK ABOUT ATOMIC ‘STABILITY’ AND VALANCE SHELLS
ATOMS WILL LOSE, GAIN OR SHARE ELECTRONS TO FILL OR EMPTY THEIR OUTERMOST SHELLS
THIS IS THE BASIS FOR ION FORMATION AND FOR CHEMICAL BONDING
USE Na, CL, K, AND Ca AS EXAMPLES

15. Behavior of atoms and outer electron shells
Atoms “want” to have completely emptied or completely filled outer electron shells.
Atoms will gain, lose, or share electrons to fill or empty their outer shells.
This is the basis for chemical bonds and the formation of ions

16. electron shell = orbital = valence shell = regions that hold electrons

17. Formation of ions

18. Gaining or Losing Electrons
Gaining Electrons
If the outer shell is almost full, gaining electrons is likely to happen
Losing Electrons
If the outer shell is almost empty, losing electrons is likely to happen 1- 1+
Note that both of these events will result in the creation of an ion.

19. Atoms lose an electron and become a positive ion.
Atoms gain electrons and become a negative ion.
4 protons: 4+
5 electrons: 5-
Charge: 1-
4 protons: 4+
3 electrons: 3-
Charge: 1+

20. (not from your text)
NOTE THAT WHOLE MOLECULES CAN ALSO BE IONIZED--

21. Functions of Ions Generate Electricity (membrane potentials)
e.g., neurons of your brain and nervous system (sodium, potassium, and calcium)
Regulate/initiate cellular events
e.g., help initiate muscle contraction, release of neurotransmitters, expression of DNA, activate enzymes (calcium), blood clotting
Building materials
e.g., Calcium (and phosphate) is part of bones
Regulate pH/acidity
HCO3- (bicarbonate ion)

22. CHEMICAL BONDING AND MOLECULES

23. CHEMICAL BONDING
Two or more atoms can bind together to form a molecule.
There are 3 major types of chemical bonds
Ionic Bonds
Covalent Bonds
Hydrogen Bonds
Create molecules
do NOT create molecules

24. Ionic Bonds
WRITE ON BOARD WHAT AN IONIC BOND IS: BOND DUE TO THE ATTRACTION OF OPOSITE CHARGES

25. Formation of an Ionic Bond
Ionic bonds are usually formed when two atoms happen to be in close proximity and exchange electrons and become oppositely charge ions.
The atoms are then held together by the attraction of opposite charge
Strength:

26. Covalent Bonds
BOND FORMED WHEN ATOMS SHARE ELECTRONS TO FILL THEIR OUTER SHELLS

27. When an electron pair is shared, both atoms get to “count” the other atom’s electron as if it was part of their own valance shell.

28. Covalent Bonds:
Atoms share electrons
Strength:

29. Polar and Non-polar Bonds/Molecules
Non-Polar = electrons are shared equally
the entire molecule is neutral and uniformly charged.
Tends to mix well with other non-polar substances
Don’t mix well with water
Polar = electrons are not shared equally
then entire molecule is neutral overall, but has regions/areas that are + or – charged
Tends to mix and dissolve well with other polar things
LIKES WATER/mixes with water
WATER IS AN IMPORTANT POLAR MOLECULE

30. Polar (and charged)
Hydrophilic
Water soluble
nonpolar
Not water soluble
(lipid soluble)
Hydrophobic

31. Hydrogen bonds ATTRACTION BETWEEN A HYDROGEN AND AN OXYGEN OR NITROGEN
CAUSED BY POLAR CHARGES

32. Hydrogen Bonds
Are attractive forces between a hydrogen and an oxygen or a hydrogen and a nitrogen
NOT based on electron transfer or sharing
Hydrogen bonds can exists between:
1. two different molecules--resulting in their
being held together.
two different parts of the same molecule—
resulting in the bending/folding of the molecule.
But hydrogen bonds don’t create molecules the way that a covalent or ionic bond does.

33. Comments on H-bonds
individual hydrogen bonds are weak, the collective influence of many hydrogen bonds can be significant
The bending of molecules with hydrogen bonds creates the final 3D shape of proteins
Form between water molecules
Hold DNA strands together
H-bonds are weak bond formed between two polar molecules based on opposite charges attracting (not based on electron sharing)