1. Entrance Question
Complete “I see, I think, I wonder” for the image below.
I see _______________________________________.
I think ______________________________________.
I wonder ____________________________________.
A B C

2. Elements and Compounds

3. Elements
There are currently 118 elements that have been identified, though only 98 of them are naturally occurring.

4. Elements in the Universe
In our universe, hydrogen makes up 75% of all matter!
Helium makes up about 20% of all matter.
Oxygen is the 3rd most abundant element.

5. Elements in the Earth
In the Earth’s crust, oxygen is the most abundant element (46.6%).
Silicon is the second most abundant element (27.7%).
Aluminum (8.1%), iron (5.0%), calcium (3.6%), sodium (2.8%), potassium (2.6%). and magnesium (2.1%) complete the list of elements that account for approximately 99% of the total mass of the earth's crust.

6. Elements Elements are pure substances.
Made of only one kind of material, has definite properties, and is the same all throughout.
Elements are the simplest pure substance.
They cannot be broken down into simpler substances without losing their identity.

7. Elements and Atoms
The smallest particle of an element that has the properties of that element is called an atom.
Atoms: the building blocks of matter.
Atoms of the same element are alike; atoms of different elements are different.

8. Elements and Atoms
In the center of every atom is a nucleus containing:
Protons (positive charge)
Neutrons (no charge)
In constant motion on the outside of the nucleus are negatively charged electrons.

9. Chemical Symbols This is a shorthand way of representing the elements.
Symbols are usually one or two letters.
Usually taken from the name of the element:
Carbon-C, Calcium-Ca, Hydrogen-H, Iodine-I, Oxygen-O, Chlorine-Cl

10. Chemical Symbols Atomic number: 2 Atomic mass: 4.00 amu
(number of protons)
Atomic mass: 4.00 amu
(number of protons + neutrons)
Fun Fact:
602,213,665,200,000,000,000,000 amu in
1 gram

11. Chemical Symbols Some symbols come from their Latin name:
Gold - Au -- aurum
Silver - Ag -- argentum
Iron - Fe -- Ferrum
Mercury - Hg -- hydrogyrum

12. Compounds Pure substances made up of more than one element.
2 or more elements chemically combined.
Ex: H2O, NaCl, C6H12O6, CO2
Unlike elements, compounds can be broken down into simpler substances.
You cannot separate compounds by physical means. This only happens through a chemical reaction.
(water) (salt) (glucose) (carbon dioxide)

13. Compounds Demo
Mystery Substance 1- NaHCO3 (solid) Mystery Substance 2 - CH3COOH (liquid) NaHCO3 + CH3COOH → CO2 + H2O + Na+ + CH3COO-

14. Compounds
The properties of the elements that make up a compound are often quite different from the properties of the compound itself.
Sodium - Na -- highly reactive metal
Chlorine - Cl -- poisonous gas
Combined: Sodium Chloride - NaCl --table salt

15. Molecules Compounds are made of molecules.
A molecule is 2 or more atoms chemically bonded.
Water-2 atoms of hydrogen and one atom of oxygen-together they form one molecule of H2O.
A molecule is the smallest particle of a compound that has all the properties of that compound.
Just as all atoms of a certain element are alike, all molecules of a certain compound are alike.

16. Chemical Formulas A shorthand way of representing compounds.
Ex: NH3 - ammonia, C3H7OH - rubbing alcohol
Sometimes, the formula represents a molecule of one kind of element.
These are called diatomic molecules. This is how that element is naturally found.
O2-Oxygen H2-Hydrogen Cl2-Chlorine

17. Chemical Formulas
Subscripts are small numbers used in chemical formulas.
They are placed to the lower RIGHT of the chemical symbols.
Subscripts represent the number of atoms of an element in a compound.
Examples:
CO2 = 1 atom of carbon and 2 atoms of oxygen.
H2SO4 = 2 atoms of hydrogen, 1 atom of sulfur and 4 atoms of oxygen

18. Chemical Formulas Practice
a. KNO3 b. K2CO3 c. NH4NO2 d. BaSO4 e. HgNO2

19. Chemical Formulas Practice
f. Hg2Cr2O7 g. ZnCrO4 h. Fe(OH)2 i. Al(NO3)2 j. Fe2(Cr2O7)3

20. Entrance Questions (Review)
Directions: Label each as an element or compound: 1.) _______________ Copper (Cu) 2.) _______________ Ammonia (NH3) 3.) _______________ Mercury (Hg) 4.) _______________ Starch (C6H10O5) 5.) How many atoms of hydrogen are in starch? 6.) How many atoms of nitrogen are in ammonia?

21. Atoms Review Element: Carbon
Element: Carbon

22. Elements Pure substance; one type of atom Hydrogen (H) Helium (He)
Gold (Au)
Copper (Cu)
Mercury (Hg)
What are a few more?
Diatomic molecules: (H2, N2, O2, etc.)
Element existing in the form of atoms
Element existing in the form of diatomic molecules

23. Compounds Pure substance; made of more than one type of element
NaCl (salt)
CO2 (carbon dioxide)
H2O (water)
NaHCO3 (baking soda)
Compound whose molecules consist of one atom of an element and two atoms of another element

24. Mixtures
combination of two or more substances that have not been combined chemically
can be separated into their original parts by physical means (Ex: distillation of liquids, separating magnetic and non-magnetic solids using a magnet, etc.)
have many of the properties of their original parts

25. Mixtures

26. Mixtures Mixture of element and element
Mixture of molecule and molecule

27. Mixtures Mixture of an element and a molecule
Mixture of a compound and a molecule

28. Review: Can you identify the following?
You will be shown a series of photos. Tell if each photo represents an item composed of an element, compound, or mixture.
Review:
An element contains just one type of atom.
A compound contains two or more different elements joined together chemically.
A mixture contains two or more different substances that are only physically joined together, not chemically.
A mixture can contain both elements and compounds.

29. Element, Compound, or Mixture?
Rocks

30. Element, Compound, or Mixture?
Rocks

31. Element, Compound, or Mixture?
Copper

32. Element, Compound, or Mixture?
Copper (Cu)

33. Element, Compound, or Mixture?
Jelly Beans

34. Element, Compound, or Mixture?
Jelly Beans

35. Element, Compound, or Mixture?
Table Sugar

36. Element, Compound, or Mixture?
Table Sugar (C12H22O11)

37. Element, Compound, or Mixture?
Tea

38. Element, Compound, or Mixture?
Tea

39. Element, Compound, or Mixture?
Salt

40. Element, Compound, or Mixture?
Salt (NaCl)

41. Element, Compound, or Mixture?
Neon Gas

42. Element, Compound, or Mixture?
Neon Gas (Ne)

43. Element, Compound, or Mixture?
Salad

44. Element, Compound, or Mixture?
Salad

45. Element, Compound, or Mixture?
Pure Water

46. Element, Compound, or Mixture?
Pure Water (H2O)

47. Element, Compound, or Mixture?
Aluminum

48. Element, Compound, or Mixture?
Aluminum (Al)

49. Element, Compound, or Mixture?
Lemonade

50. Element, Compound, or Mixture?
Lemonade

51. Element, Compound, or Mixture?
Silver

52. Element, Compound, or Mixture?
Silver (Ag)

53. Element, Compound, or Mixture?
Sand

54. Element, Compound, or Mixture?
Sand

55. Entrance Question
A, B, C, and D are all examples of different substances. Label each example as an element, compound, or mixture. Explain your answers!
A B C D

56. Period Table of Elements
Review
Elements:
A pure substance containing only one kind of ____________.
An element is always the same all the way through.
An element _____________ be separated into simpler materials (except during nuclear reactions).
Over 100 existing elements are listed and classified on the ____________________.
atom
cannot
Period Table of Elements

57. Review Atoms: An atom is the smallest part of an element.
Ex: One atom of Hydrogen
At the center of an atom is a ________________, containing ______________ and ________________.
Atoms have are neutral in charge because they have an equal amount of ______________ and _____________.
An atom’s atomic number tells the number of __________ in the atom’s nucleus.
An atom’s atomic mass does not include the atom’s _____________ because they are extremely small.
nucleus
protons
neutrons
protons (+)
electrons (-)
protons
electrons

58. Review
Compounds:
A pure substance containing two or more kinds of _______________.
The atoms are _________________ combined in some way. Often times (but not always) they come together to form groups of atoms called molecules.
A compound is always the same throughout.
Compounds ___________________ be separated by physical means. Separating a compound requires a chemical reaction.
The properties of a compound are usually _____________ than the properties of the elements it contains.
elements
chemically
cannot
different

59. Review
Mixtures:
Two or more ________________ or _________________ NOT chemically combined.
There is no chemical reaction between its substances.
Mixtures _____ be separated into their components by physical means.
The properties of a mixture are ____________ to the properties of its components.
elements
compounds
can
similar

60. Roundtable Consensus Group Practice
Why Roundtable Consensus Groups?
All students are involved; students must work together; groups have great discussions/debates.
Rules:
Students work on their own for each question.
Once all students are finished with a question, the group discusses their answers. The group must agree on ONE final answer before moving on to the next question.
If there is a disagreement in answers, be respectful while giving your reasoning.
Students may NOT work ahead of their group!

61. Roundtable Consensus Group Practice

62. Entrance Question Draw a model of one atom of Lithium (Li).
***Round its mass to the nearest whole number (7).
Hint: The atomic number tells us the number of ___________ in the nucleus.
Hint: The atomic mass is the sum of protons and neutrons.

63. Elements, Compounds, & Mixtures Wkst

64. Element, Compound, & Mixture Practice

65. Element, Compound, & Mixture Practice
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