Download Chapter 4: Formation of Compounds

Section 4.1: The Variety of Compounds
Objectives: Distinguish the properties of
compounds from those of the elements of which
they are composed, Compare and contrast the
properties of sodium chloride, water and carbon
dioxide
What is an element?
What is a compound?
How do they differ?
** Compound formation is only a rearrangement of
valence electrons**
Physical/Chemical Properties of
Salt:
Compound; Chemical Formula: NaCl
1. white solid at 200C
2. crystalline shape
3. brittle
4. melts at 8000C
5. dissolves easily in water
6. non-conductor when solid, but conducts when
molten/liquid
7. nonreactive/stable compound
NaCl
Properties of Sodium
Element; Symbol: Na
1. shiny, silvery-white, soft solid at room temp
2. melts at 980C
3. reacts with oxygen to form sodium oxide, Na2O
4. reacts with water to form hydrogen gas, and sodium
hydroxide, NaOH (this is why its pure form is stored in
oil)
5. never found free in the environment b/c of its high
reactivity
Sodium
 http://www.youtube.com/watch?v=MTcgo46nxNE
Properties of Chlorine
Element; Symbol: Cl2 (this is what’s called a diatomic
element)
1.pale green, poisonous, gas @ room temp
2. odor
3. kills living cells, disinfects
4. boiling point is a mere –340C
5. among the most reactive elements
Chlorine
Reaction of Sodium and Chlorine
http://www.youtube.com/watch?v=Mx5JJWI2aaw
Carbon Dioxide:
Compound; Chemical Formula: CO2
1. colorless gas at room temp
2. slightly soluble in water
3. freezing point = -800C, DRY ICE
4. relatively stable; puts out fire
5. ingredient in photosynthesis
6. tasteless and odorless
http://www.youtube.com/watch?v=e7tf2MeXuQg
http://www.youtube.com/watch?v=8AN_XMcD3yI
Properties of Carbon
Element; Symbol: C
1. fairly unreactive solid at room temp
2. at higher temps, will react with MANY elements
3. burns easily and is an excellent heat source
4. carbon compounds are the basis of all living things
Carbon
Properties of Oxygen
Element; Symbol: O2
1. colorless, odorless, tasteless
2. supports combustion (it is not flammable by itself)
3. slightly soluble in water
4. very reactive
5. 21% of air you breathe
6. most abundant element in the Earth’s crust
Oxygen
Physical/Chemical Properties of
Water
Compound; Chemical Formula: H2O
1. gas at 1000C
2. solid at 00C
3. non-conductor (when distilled or pure)
4. great solvent
5. stable
6. good medium for other reactions to occur in
7. other ingredient in photosynthesis
Water (H2O)
Properties of Hydrogen
1. Lightest most abundant element in the universe
2. Odorless, tasteless, colorless nonmetal gas
3. Reactive compound that occurs in a variety of
compounds
4. Does not conduct electricity and only slightly soluble
in water
Hydrogen
 http://www.youtube.com/watch?v=s0zxF66nbRU