1. BASIC CHEMISTRY ATOMS, ELEMENTS AND HOW THEY BEHAVE

2. In this Universe….. There is……. Matter – anything that has MASS and takes up space. Space – what is not matter. Which is there more of????

3. WHERE DID MATTER COME FROM? Big Bang Approx. 13 BYA Produced enormous amounts of energy! Energy eventually “chilled” enough to form basic building blocks of matter Evidence??? Expanding Universe Red-shift Background radiation

4. BUILDING AN ATOM Atoms = basic unit of matter Made of… Electrons (e-) small, no mass, negatively charged Protons (p+) Has mass, positively charged Neutrons (n 0) Has mass, no (neutral) charge

5. ATOM STRUCTURE Protons and Neutrons are located near the center of the atom and form the NUCLEUS Electrons orbit around the nucleus in specific electron orbitals/shells. Why are electrons attracted to the nucleus? What keeps the electrons from “crashing in?”

6. KEY POINT!!!! Atoms, can have DIFFERENT combinations of electrons, neutrons and protons! These different combinations makes the atoms BEHAVE differently and have different properties.

7. INTRODUCING THE ELEMENTS!

8. SO WHERE DID ALL THESE DIFFERENT ATOMS COME FROM???? Telling the story of matter…. -Big Bang  HUGE amount of energy released -Energy “chills” and starts to form basic building blocks of matter -First atoms form  Hydrogen and Helium. -Hydrogen attracted to other hydrogen  Big balls of hydrogen -FUSION REACTION (aka starts)  smaller atoms fuse together to form heavier elements (carbon, nitrogen, phosphorus sulfur). -SUPER FUSION  In supernovas even heavier elements are formed.

9. WHERE THIS LEAVES US! Approx 5 BYA… -some leftover space debris from star cycles start to coalesce in different ways -Hydrogen collected in center starts a fusion reaction = our sun ignites -Circling debris coalesces to form planets

10. WHAT WE HAVE ON EARTH Atoms can exist in varying forms on earth -Compounds -Two or more different atoms bonded together -Ex. H 2 0, CH 4 -Elements -substances consisting of only one type of atom. -A single atom is the smallest amount of an element you can have. -Ex. O 2, H 2

11. STRUCTURE OF AN ATOM P+P+ P+P+ N N e-e- Nucleus Orbit e-e-

12. STRUCTURE OF AN ATOM P P N N e e Nucleus Orbit e e e e e e e e e

13. EACH ORBIT IS A SPECIFIC DISTANCE FROM THE NUCLEUS. P P N N e e Structure of an Atom

14. DISTANCE INCREASES AS ENERGY LEVEL INCREASES. P P N N e e Structure of an Atom

15. ATOMIC THEORIES AND DISCOVERIES Dalton: Late 19th century - thought the atom was nothing more than a tiny indivisible sphere

16. Rutherford’s view of the atom Nucleus contains protons and neutrons Number of protons dictates which element. Electrons circle nucleus in orbits.

17. Bohr’s view of the atom Electron orbits exist at only certain energy levels (distances) from the nucleus.

18. Bohr’s view of the atom Each orbit holds only a certain number of electrons Orbit 1 – max 2 Orbit 2 and 3 – max 8

19. Bohr’s view of the atom Valence Electrons: Electrons in the outermost orbit; - determine which atoms can form bonds together

20. Bohr’s view of the atom Elements with full “outer shells” do not react Noble or “Inert” gases: He, Ne, Xe

21. THE PERIODIC CHART Atomic number = number of protons Atomic Mass is the “approximate” number of protons + neutrons If atom has a charge of zero, Electrons = Protons

22. IONS atoms with a positive or negative charge created by adding or losing electrons How do we get a + ion??

23. ISOTOPES atoms with the same number of protons and electrons but different neutrons

24. COMPOUNDS Two or more atoms bonded together in a set proportion Molecule Single unit of a compound Contains more than one atom, BUT can be the same type of atom (O2, N2)

25. COMPOUNDS Strength of bonds depends on length, angle and Type of bond Ionic- Covalent- Bonding Animations Bonding Animations

26. TYPES OF BONDS Ionic: one atom gives electrons to another, creates opposite charges

27. TYPES OF BONDS Covalent: atoms share electrons

28. Bonding – depends on valence e - ’s An atom with < 8 valence e - ’s can bond with other atom(s) to fill up the outer shell (reach 8) Examples: Na (1Ve) bonds with Cl (7Ve’s) C (4Ve) bonds with 4H (1 Ve each) O (6 Ve) bonds with 2H (1 Ve each)

29. TYPES OF BONDS Which do you think is stronger? Ionic: two atoms attracted by opposite charges? OR Covalent: two atoms holding on to same electrons

30. MIXTURES VS. COMPOUNDS Mixtures have “ingredients” that do not bind chemically with each other Each substance keeps its own property No definite proportions Types: solution, suspension, colloid

31. CHEMICAL FORMULAS A chemical formula tells us three things: What elements are involved How many atoms of each you have How many molecules you have

32. CHEMICAL FORMULAS Ex: 3C 6 H 12 O 6 This means there are 3 molecules of (C 6 H 12 O 6 which is glucose) 1 molecule of (C 6 H 12 O 6 ) contains 6 Carbon atoms, 12 Hydrogen atoms and 6 Oxygen atoms So how many H’s total are represented in this formula?

33. MIXTURES VS. COMPOUNDS Compounds have different properties than any of the elements that make it up Parts are Chemically bound Definite proportions required

34. MIXTURES VS. COMPOUNDS Mixtures have ingredients that do not chemically bind to one another Mixture has same properties as ingredients No definite proportions needed

35. TYPES OF MIXTURES Solution – Homogeneous mixture equal composition throughout 2 or more substances; solvent and solute Solute is individual ions or molecules Can you think of an example?

36. TYPES OF MIXTURES Suspension – heterogeneous looks uniform when shaken or stirred; Separates upon sitting (no agitation) Can you think of an example?

37. TYPES OF MIXTURES Colloid – Mixture of very tiny particles of dispersed in another substance; Suspended but do not settle out Can you think of an example?

38. PROPERTIES OF WATER Most important inorganic compound in living systems Most important inorganic compound in living systems Nearly all chemical reactions occur in water Nearly all chemical reactions occur in water

39. PROPERTIES OF WATER Polar covalent Share electrons but not equally – creates slight (-)charge in the O and a slight (+) charge in the H’s of waterShare electrons but not equally – creates slight (-)charge in the O and a slight (+) charge in the H’s of water

40. PROPERTIES OF WATER Polarity of Water movie

41. PROPERTIES OF WATER Cohesion Water molecules stick to other water molecules Creates a high surface tension

42. PROPERTIES OF WATER Universal Solvent Universal Solvent Polarity of water allows it to interact with neighboring polar or ionic molecules Polarity of water allows it to interact with neighboring polar or ionic molecules Dissolves or suspends many substances Dissolves or suspends many substances What will not dissolve in water? What will not dissolve in water?

43. PROPERTIES OF WATER EXAMPLE NaCl + H 2 O  Na + + Cl - + H 2 O oxygen attracts sodium oxygen attracts sodium hydrogen attracts chloride hydrogen attracts chloride sodium & chloride separate as ionic bonds are broken

44. Adhesion Water molecules stick to other substances with partial charge Water Glass Tube Properties of Water

45. Water has a high specific heat Specific heat is the amount of energy needed to raise 1 gram of water 1 degree. Water absorbs a lot of energy before its temp goes up Keeps earth’s temperature stable! Properties of Water

46. Concept of pH – see pH scale and worksheet