1. Elements, Compounds and Mixtures
Oh My!

2. Atoms vs. Molecules Review: What is an atom?
The smallest part of an element
Some atoms are single and other atoms are coupled together.
When 2 or more atoms are coupled together, they are called molecules.
What is the difference between atoms and molecules?
Atoms are single (just 1)
Molecules are couples (more than 2 atoms)
Atoms vs. Molecules

3. Molecules Just like elements, molecules are represented by symbols.
Sometimes molecules are made of atoms that are the same
The oxygen molecule: has 2 atoms of the element oxygen
Symbol: O2
Sometimes molecules are made of atoms that are different
A water molecule: has 2 atoms of the element hydrogen and 1 atom of the element oxygen
Symbol: H2O
Molecules

4. When everything is the same, it is called a pure substance
All the particles in pure gold are gold atoms.
All the particles in pure water are water molecules.
Pure Substance
Meet the Elements

5. If the atoms in a material are all the same (1 type), the material is an element
Cannot be broken down into simpler substances
Properties don’t change
Examples: oxygen, hydrogen, sodium, chlorine, carbon
Elements Are Pure

6. If you have 2 or more elements (different types of atoms) chemically combined = compound
Can be separated chemically
The elements that form a compound do not keep their individual properties-
A new substance with completely different properties is formed
Examples: water, salt, sugar, carbon dioxide gas
Compounds are always molecules because they have more than 2 different atoms and a molecule is 2 or more atoms
Compounds Are Pure

7. Sodium (Na) is a soft metal that explodes when combined with water
Chlorine (Cl) is a poisonous gas
But when chemically combined we get an edible, white solid that we know as table salt (NaCl)
Molecule/compound activity
Water (H2O) = 2 gases form a liquid
Compounds

8. are always are always combine to form are made of 2 or more
can be in the form of
are always

9. Mixtures are 2 or more substances (can be elements or compounds or both) that are physically together
The components of a mixture can be separated physically
Each part of the mixture keeps its individual properties
Examples: trail mix, salt water (NaCl + H2O)
Which one is which interactive activity
Mixtures Are Not Pure

10. 2 Types of Mixtures Heterogeneous: Homogenous: Means "different"
Unevenly mixed throughout the substance
Pizza
Salsa
Chicken soup
Chex mix
Homogenous:
Means "the same"
Evenly mixed throughout the substance
Kool-Aid
Lemonade
Tea/coffee
Salt water
2 Types of Mixtures

11. Matter Elements Compounds Mixtures
Made of 2 or more elements chemically together
Can be separated chemically
Examples: Water (H2O)
Made of 1 type of atom
Cannot be separated
Example: Hydrogen (H), Oxygen (O)
Pure substances
Matter
2 or more substances
Properties don’t change
Made of 2 or more substances physically together
Can be separated physically
Example: salt water (NaCl + H2O)
Mixtures