1. Notes: The Chemicals of Life

2. Elements
Everything is made up of ELEMENTS, the SIMPLEST chemical substance and CAN’T be BROKEN down
Are elements biotic or abiotic?

3. Essential Elements ONLY 25 elements are ESSENTIAL to living organisms
99% of the human body is made up of:
oxygen (65%)
carbon (18%)
hydrogen (10%)
nitrogen (3%)
calcium (1.5%)
phosphorous (1%)
Most of the human body is made up of water, H2O, with cells consisting of 65-90% water by weight. Therefore, it isn't surprising that most of a human body's mass is oxygen. Carbon, the basic unit for organic molecules, comes in second. 99% of the mass of the human body is made up of just six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus.
Oxygen (65%)
Carbon (18%)
Hydrogen (10%)
Nitrogen (3%)
Calcium (1.5%)
Phosphorus (1.0%)
Potassium (0.35%)
Sulfur (0.25%)
Sodium (0.15%)
Magnesium (0.05%)
Copper, Zinc, Selenium, Molybdenum, Fluorine, Chlorine, Iodine, Manganese, Cobalt, Iron (0.70%)
Lithium, Strontium, Aluminum, Silicon, Lead, Vanadium, Arsenic, Bromine (trace amounts)

4. Trace Elements
TRACE elements are found in living organisms in very SMALL amounts.
Potassium
Sulfur
Sodium
Magnesium
Copper
Zinc
Selenium
Molybdenum
Fluorine
Chlorine
Iodine
Manganese
Cobalt
Iron
Lithium
Strontium
Aluminum
Silicon
Lead
Vanadium
Arsenic
Bromine

5. Atoms
ELEMENT = Same ATOMS!
They are pure substances

6. Atom Atoms have PROTONS, NEUTRONS, and ELECTRONS
The nucleus (center) contains PROTONS and NEUTRONS
PROTONS = +
NEUTRONS = NO charge

7. Atom Structure

8. Electrons ELECTRONS are found around the nucleus in a CLOUD
ELECTRONS are negative (-)
Electrons = Protons

9. Who has heard of The Periodic Table of Elements?

10. Hydrogen What is the symbol used to represent hydrogen?
What is hydrogen’s atomic # (# of protons)?
What is hydrogen’s atomic mass (Protons PLUS neutrons)?

11. Potassium What is Potassium’s symbol?
How many protons does potassium have?
How many neutrons?
How many electrons?

12. Calcium What is the symbol for calcium? _____
How many electrons? _____
How many protons? _____
How many neutrons? _____
Atomic mass? _____

13. Krypton Symbol? _____ Protons? _____ Neutrons? _____ Electrons? _____
Mass? _____
Isotopes of the Element Krypton with a Known Natural Abundance (stable)
Mass Number---Natural Abundance % % % % % %
37 Known Isotopes of the Element Krypton
Isotope mass numbers run from 69 to 100
What is this?

14. Isotopes
Atoms of the same element that have different number of NEUTRONS
Ex: Carbon 12 = 6 protons and 6 neutrons
Carbon 13 = 6 protons and 7 neutrons
Carbon 14 = 6 protons and 8 neutrons
The nucleus of most isotopes are unstable and often break giving off RADIATION when it breaks down

15. Ways to use isotopes
Diagnose or treat diseases (detection of radiation can indicate cancer)
Thyroid gland functioning properly (use radioactive Iodine, absorbed by thyroid gland)
Determine the “HALF-LIFE” of an item (fossil, rock, etc)