1. Basic Chemistry

2. Vocabulary
Atoms: Smallest particle of an element that has all the properties of matter (anything that occupies space and has mass):
Protons- particles in the nucleus with positive charge
Electrons- particles orbiting around nucleus with negative charge
Neutrons- particles in the nucleus with no charge (neutral)

3. Vocabulary Elements: Simplest form of a pure substance
Molecule: when two or more atoms join together
(ex O2)
Compounds: Two or more different elements chemically combined to form a new substance
(ex. NaCl – sodium chloride, table salt)

4. Counting Atoms

5. Periodic Table
Many elements with some some directly needed and some not

6. Trace Elements
Elements that are essential for an organism to live but only in small amounts
Different organisms require different trace elements

7. Trace Elements Some examples: Sometimes added to ‘fortified foods’
Iron (Fe) critical to transport oxygen in blood
Iodine (I) is important for producing a hormone (iodized salt)
Flourine (F) helps reduce tooth decay
Sometimes added to ‘fortified foods’

8. Quick Search

9. Periodic Table
Lots of numbers, what do they mean?

10. Using the Periodic Table
Atomic Number
Equal to # protons = # electrons
Periodic Table is arranged by this number
Symbol
“Shorthand” for the element – Note 2nd letter is always lowercase
Atomic Mass Number
Total AVERAGE mass of Protons + Neutrons + Electrons 17 Cl
35.5

11. Isotopes
An isotope is a variation of an element (same protons) but can have diff. # of neutrons

12. Radioactive Isotopes
An isotope that is unstable and decays, spontaneously giving off particles and energy
Can be damaging to living organisms
Can break apart DNA and other molecules, or change the chemical bonds
Can be used to help
Radioactive dating
Tracers

13. Radioactive tracers are frequently used in medical diagnosis.
Sophisticated imaging instruments are used to detect them.
An imaging instrument that uses positron-emission tomography (PET) detects the location of injected radioactive materials
Student Misconceptions and Concerns
• The dangers posed by certain chemicals in our food and broader environment have sometimes misled people to associate chemicals with harm. People might not want chemicals added to their food or in their environment. Students often fail to appreciate the chemical nature of our bodies and our world and the potential harm or benefits of naturally occurring chemistry. They often fail to understand why “natural” does not necessarily mean good. (Consider presenting a long list of naturally occurring toxins to make this point.) Your class may benefit from a class discussion of these misconceptions about our attitudes toward chemicals.
Teaching Tips
• The half-lives of many radioactive substances, especially those used for dating fossils, might lead some students to expect very long periods of decay for any radioactive substance. This might even be alarming if students are someday asked to consume a radioactive substance for a medical test. However, some medically significant isotopes have relatively short half-lives. Radioactive iodine-131 is often used to diagnose or treat certain thyroid problems. Its half-life of eight days means that it will decay quickly.
• Depending upon where you are teaching, radon in homes may be a common problem and pose a significant health risk. If you are in a high-radon region, consider adding details about home remediation methods and expenses or have students research the topic and report back.

15. Valence Electrons An electron on the outermost energy shell of an atom
Important to understand because this is a key factor in how atoms will BOND with each other
Octet rule – stable atom will have 8 electrons in that outer shell, atoms ‘want’ 8 electrons, they ‘want’ to be stable

16. # of Valence Electrons

17. Types of Chemical Bonds
Covalent- Two elements bond by sharing electrons (strongest bond type)

18. Animation: Covalent Bonds

19. Types of Chemical Bonds
Ionic- Two elements bond by transferring electrons to create ions that attract together (+ is attracted to - after an electron is transferred)

20. Animation: Ionic Bonds

21. Water Model
Each students should take a water molecule model. Look at it, hold it. Examine how it interacts with other student’s water molecules?
What is holding the hydrogens to the oxygen?
How can the water molecules connect together?
What is different about these two bonds?

22. Penny and water droplets
Move to the back of the room to where there is a penny. Take a pipet and put one drop of water on the penny.
Predict how many droplets will fit on the penny.
Next put as many droplets on the penny as you can.

23. Types of Chemical Bonds
Hydrogen – Important bond for biology. A molecule with an uneven charge on it, will bond to another unevenly charged molecule

24. Animation: Water Structure and Hydrogen bonds

26. Polarity Some electrons are not shared evenly in covalent bonds.
One end, or pole, of the molecule has a partial negative charge while the opposite pole has a partial positive charge.

27. Polarity
Poles attract opposite charges – polar substances dissolve in water
Nonpolar substances do not dissolve in water
Important with molecules trying to pass through a membrane
Polar head
Non-polar tail