1. Classifying Matter: Elements, Compounds, and Mixtures

2. Atoms Elements Compounds Molecules
Pure Substances
A sample of matter that has definite chemical and physical properties.
Atoms
Elements
Compounds
Molecules

3. Elements
pure substance that cannot be separated into simpler substance by physical or chemical means.

4. consists of only one kind of atom,
cannot be broken down into a simpler type of matter by either physical or chemical means, and
can exist as either atoms (e.g. argon) or molecules (e.g., nitrogen).
A molecule consists of two or more atoms of the same element, or different elements, that are chemically bound together. Note that the two nitrogen atoms which comprise a nitrogen molecule move as a unit.

5. Compounds
Pure substance composed of two or more different elements joined by chemical bonds.
Made of elements in a specific ratio
that is always the same
Has a chemical formula
Can only be separated by
chemical means, not physically
H2O
NaCl
CO2

6. consists of atoms of two or more different elements bound together,
can be broken down into a simpler type of matter (elements) by chemical means (but not by physical means),
has properties that are different from its component elements, and
always contains the same ratio of its component atoms.

7. Mixtures
A combination of two or more pure substances that are not chemically combined.
substances held together by physical forces, not chemical
No chemical change takes place
Each item retains its properties
in the mixture
They can be separated physically
Chem4kids.com

8. Note that a mixture:
consists of two or more different elements and/or compounds physically intermingled,
can be separated into its components by physical means, and
often retains many of the properties of its components

9. Mixtures vs. Compounds

10. 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 atoms joined together.
A mixture contains two or more different substances that are only physically joined together, not chemically.
A mixture can contain both elements and compounds.

11. Element, Compound, or Mixture?
Rocks

12. Element, Compound, or Mixture?
Rocks

13. Element, Compound, or Mixture?
Copper

14. Element, Compound, or Mixture?
Copper Cu

15. Element, Compound, or Mixture?
Jelly Beans

16. Element, Compound, or Mixture?
Jelly Beans

17. Element, Compound, or Mixture?
Table Sugar

18. Element, Compound, or Mixture?
Table Sugar
C12H22O11

19. Element, Compound, or Mixture?
Diamond

20. Element, Compound, or Mixture?
Diamond C

21. Element, Compound, or Mixture?
Tea

22. Element, Compound, or Mixture?
Tea

23. Element, Compound, or Mixture?
Salt

24. Element, Compound, or Mixture?
NaCl
Salt

25. Element, Compound, or Mixture?
Pure Water

26. Element, Compound, or Mixture?
Aluminum

27. Element, Compound, or Mixture?
Lemonade

28. Element, Compound, or Mixture?
Sand

30. Homogeneous Mixture – Molecules are mixed up in an even distribution
This mixture appears to be a single substance
Ex- sugar water, lemonade, kool-aid, air
Heterogeneous Mixture – Molecules are not mixed in an even distribution
Ex – sand in a bucket of water, muddy water.

31. Atomicity of molecules
Monoatomic – molecules that contain only one atoms(Argon)
Diatomic – molecules that contain only two atoms (H2,
Triatomic – H2O, CO2