elements vs. compounds

1. Element vs
Compound

2. Learning Goals
 Define compounds.
 Identify and name some common
compounds.
 Explain how compounds are formed.
 Compare element and compound.
 Classify substances as element or compound.

3. RECAP

4. What’s an element?
 Remember…. A pure substance….that can
not be broken down into another
substance…..
 Name 5 elements?

5. Discussion: Do you think elements
combine? Explain your thinking….
provide evidence?
Salt Water Sugar

6. Compound
write this down in your notebook
 Pure substance composed of two or more different
elements joined by chemical bonds.
 These chemical bonds can only be separated by other
chemicals. You can not physically pull, cut, or tear a
compound apart.
 Made of elements in a specific ratio .

7.  Sodium is an extremely
reactive metal that dulls
almost instantly upon
exposure to air.

8.  Chlorine is a yellow gas
with a pungent odor. It is
highly reactive and
poisonous.

9.  The compound formed
by sodium and chlorine
is table salt.
 The properties of a compound are, in
general, different from the properties
of the elements that compose it.

10.  The compound formed
by sodium and chlorine
is table salt.
 The properties of a compound are, in
general, different from the properties
of the elements that compose it.

11.  A chemical formula indicates the elements present
in a compound and the relative number of atoms of
each.
 For example, H2O is the chemical formula for water; it
indicates that water consists of hydrogen and oxygen
atoms in a 2:1 ratio.
 The formula contains the symbol for each element,
accompanied by a subscript indicating the number
of atoms of that element. By convention, a
subscript of 1 is omitted.

12.  What are the element ratios for these
common chemical formulas:
 NaCl
 CO2
 C12H22O11

13.  The subscripts in a chemical formula are
part of the compound’s definition—if
they change, the formula no longer
specifies the same compound.

14.  Chemical formulas list the most metallic
elements first.
 The formula for table salt is NaCl, not
ClNa.
 In compounds that do not include a
metal, the more metal-like element is
listed first.

15.  Among nonmetals, those to the left in the
periodic table are more metal-like than those
to the right and are normally listed first.
 We write NO2 and NO, not O2N and ON.
 Within a single column in the periodic table,
elements toward the bottom are more metal-
like than elements toward the top.
 We write SO2, not O2S.

16.  Among nonmetals, those to the left in the
periodic table are more metal-like than those
to the right and are normally listed first.
 We write NO2 and NO, not O2N and ON.
 Within a single column in the periodic table,
elements toward the bottom are more metal-
like than elements toward the top.
 We write SO2, not O2S.

18. What does ratio mean?
How much of one
thing is compared to
another.

19. Compound CO is a deadly
compound… What
two elements is it
made from? What is
the ratio of
elements?
Carbon and Oxygen
Waist gas from an
engine.
Carbon Monoxide

20. Carbon Monoxide

21. Compound
NaCl/ is a common
compound… What
two elements is it
made from? What is
the ratio of
elements?
Sodium
Chlorine/Chloride
Salt

22. Sodium Chloride
A square compound under a
microscope.

23. Compound
C12H22O11 is a
common
compound… What
three elements is it
made from? What is
the ratio of
elements?
Carbon Hydrogen
Oxygen
Table sugar

24. Sugar

25. Compound SiO2is a common
compound… What
two elements is it
made from? What is
the ratio of
elements?
Silicon Oxygen
Silicon Oxide
Sand

26. 1 Silicon element
Chemically bonded to
2 Oxygen elements

27. Compound N2O is a common
compound… What
two elements is it
made from? What is
the ratio of
elements?
Nitrogen Oxygen
Nitrous Oxide
Laughing Gas

29. Discussion: What’s the difference
between an element and a
compound?
 An element contains just one type of atom.
 A compound contains two or more different
atoms joined chemically in a ratio.

30. Common examples of compound

31. Element, or Compound?
Copper

32. Element, or Compound?
Copper

33. Element, or Compound?
Table Sugar

34. Element, or Compound?
Table Sugar

35. Element, or Compound?
Diamond

36. Element, or Compound?
Diamond

37. Element or Compound,?
Neon Gas

38. Element, or Compound?
Neon Gas

39. Element, or Compound,?
Pure Water

40. Element, or Compound?
Pure Water

41. Element, or Compound?
Aluminum

42. Element, or Compound?
Aluminum

43. Element, or Compound?
Silver

44. Element, or Compound?
Silver

45. Element, or Compound?
Sand

46. Element, or Compound?
Sand

48. Compound Discovery
It is the year 2032 and you and a partner have just been asked to join
NASA on a trip to Jupiter. On this trip, your team discovered a brand new
compound that no one has ever seen. Upon further investigation, you
also noticed the compound was made up of elements commonly found
on the periodic table and ones that have also never been seen. To
introduce the world to the new compound, you need to chart the
following information:
 Name of Compound
 Colored Picture of the discovered compound
 Description of the physical and chemical properties of the
compound
 List of all of the elements that are bonded together to make up
the compound (minimum of 2, real or made up)
 Atomic #, Atomic Mass, Protons, Neutrons and Electrons written
out for each element
 Atomic Drawing of the compound. Showing how each element
bonds to the other (Protons, Neutrons and Electrons) (Each
Element wants 8 electrons in their outer roadway, so they
may share electrons/Bond)