1. Unit 3.3 “Elements & Compounds”
Mr. Ivey

2. Substances are either:
a) elements, or
b) compounds

3. Elements Compounds -simplest kind of matter
Can’t be broken down any simpler and still have properties of that element!
all 1 kind of atom.
substances can be broken down only by chemical methods
when broken down, the pieces have ∆ properties than the original compound.
made of 2 or > atoms, chemically combined (not just a physical blend!)
Elements
Compounds

4. e.g. of elements
Sodium - Na solid, silver, play doughy element reacts violently w/water

5. e.g. of elements
Chlorine - Cl Green gas Lethal if inhaled Kills bacteria 99%

6. e.g. of compounds
Sodium Chloride - NaCl Solid, white crystalline powder Used for flavoring food

7. e.g. of elements
Carbon - C Solid, Black (charcoal) not particularly harmful

8. e.g. of elements
Oxygen – O (usually expressed O2) Odorless, clear, gas not harmful, but explosive around a flame

9. e.g. of compounds
Carbon Dioxide – CO2 Odorless, clear gas deadly if inhaled in large quantities

10. e.g. of elements
Hydrogen – H (usually expressed H2) Colorless, Odorless flammable gas Highly reactive, therefore harmful

11. e.g. of elements
Fluorine – F (usually expressed F2) Pale Yellow, Odorless gas Highly toxic gas

12. e.g. of elements
Fluoride – (usually expressed F- ion) Fluorite (rock) source of fluorine & fluoride Fluoridation of water to prevent tooth decay

13. e.g. of compounds
Hydrogen Fluoride – HF Clear, irritating gas Creates HF acid causes blindness and death

14. Compound vs. Mixture Compound Mixture Made of one kind of material
Made of more than
one kind of material
Made by a
chemical change
physical change
Definite
composition
Variable

15. Which is it?
Compound
Mixture
Element

16. Elements vs. Compounds cannot be broken down Compounds Elements
Chemical
Change
can be broken down into simpler substances by chemical means, but ...
cannot be broken down
∆ that produces matter with a different composition than the original matter.

17. Properties of Compounds
Different properties than their component elements.
Due to a CHEMICAL CHANGE, the resulting compound has new and different properties:
Table sugar – carbon, hydrogen, oxygen
Sodium chloride – sodium, chlorine
Water – hydrogen, oxygen

18. Classification of Matter

19. Symbols & Formulas 117 elements Elements Compounds
have a 1 or two letter symbol
first letter always capitalized; if there is a second letter, it is written lowercase: B, Ba, C, Ca, H, He
have a formula.
Start learning the elements names and symbols listed in your Periodic Table