2. Atoms and Elements

3. Atoms are the basic units of all matter.

4. 1.Protons (+) 2.Neutrons (0) 3.Electrons (-) Atoms are composed of 3 sub-atomic particles:

5. An atom is the smallest particle of an element. Elements

6. An element is a substance that can not be broken down into simpler chemical substances.

7. Everything is made of substances called elements.

8. Each element is identified by a one- or two-letter abbreviation called a symbol.

9. Atomic number The atomic number is equal to the number of protons that an atom has. Ex. Silver has an atomic number of 47 and therefore has 47 protons

10. Atoms always contain the same number of protons and electrons Atomic # = protons = electrons

11. Atomic Mass The atomic mass is the number of protons and neutrons added together. How do you figure how many neutrons there are? Atomic mass - atomic number = number of neutrons!

12. The Fab Five Elements In Biology this year, we will be focusing on 5 main elements. They are… Carbon Hydrogen Oxygen Nitrogen Phosphorus

13. Notice just how much of the human body they compose That’s 96.8% of your total body composition!

14. Carbon Atomic Number: 6 Atomic Mass: 12.01 Carbon is the basis for organic organisms as it occurs in all living things. Makes up about 18% of human bodies Examples: found in carbohydrates, lipids, proteins and nucleic acids

15. Carbon in Chemical Structures Carbon is so common in living organisms that they can sometimes be omitted to save time. Anywhere there is a corner without a letter, that means a carbon is actually there. Carbons are represented By the letter C

16. Hydrogen Atomic Number: 1 Atomic Mass: 1.01 Hydrogen is the most abundant element in the universe Makes up about 10% of human bodies Examples: found in carbohydrates, lipids, proteins and nucleic acids

17. Hydrogen is represented By the letter H Hydrogen in Chemical Structures

18. Oxygen  Atomic Number: 8  Atomic Mass: 15.99  Animals and plants require Oxygen for respiration  Makes up about 65% of human bodies  Examples: found in carbohydrates, lipids, proteins and nucleic acids

19. Oxygen in Chemical Structures Oxygen is represented By the letter O

20. Nitrogen  Atomic Number: 7  Atomic Mass: 14.01  Nitrogen gas (N 2 ) makes up 78.1% of the volume of the Earth's air.  Makes up about 3% of human bodies  Examples: found in proteins and nucleic acids

21. Nitrogen in Chemical Structures Nitrogen is represented By the letter N

22. Phosphorus  Atomic Number: 15  Atomic Mass: 30.97  Important for proper skeletal and nervous system function  Makes up about 1% of human bodies  Examples: found in nucleic acids

23. Phosphorus in Chemical Structures Phosphorus is represented By the letter P

24. Directions: Label each of the Fab Five Elements in the chemical compound (Adenosine Triphosphate a.k.a ATP) below.

25. Directions: Label each of the Fab Five Elements in the chemical compound (glucose) below.