1. The Chemical
Nature of Matter
7.P.2A.4 Notes

2. What is MATTER? Anything that has mass and takes up space
Matter is composed of extremely small particles, too small to be seen with a classroom microscope, called atoms.

3. What is not MATTER?
Light and Sound
Sound waves

4. What is an ELEMENT?
Pure substances that cannot be changed into simpler substances.
Composed of one kind of atom
Examples: Hydrogen, Oxygen, Carbon, Nitrogen, Helium
Ex. Silver, oxygen, hydrogen, helium, and aluminum
There are as many types of elements as there are atoms more than 100.

5. What is a COMPOUND?
Pure substance that consists of two or more different types of elements chemically bonded together
Only changed into simpler substances called elements by chemical changes
One way that two or more atoms can combine is to form a molecule.
Compound can have very different properties from the elements that make up that compound
Ex. Table Salt is safe to eat, the individual elements that go into making it are poisonous

6. What is a MOLECULE?
When two or more atoms bond together, or combine they make a particle called a molecule.
Oxygen atom
Hydrogen atoms
A molecule is the smallest amount of a substance made of combined atoms that is considered to be that substance. Ex. Break water apart
Molecules can be made up of different numbers of atoms. Molecules made up of diferrent numbers of the same atom are different substances.
Water Molecule

7. The two types of chemical bonds are Ionic and Covalent Bonds
Ex. Dust particles bouncing off air molecules
Ex. When drop food coloring in water, eventually water molecules will cause the food coloring to spread throughout the water.
Ex. Molecules in tables can’t be seen easily in motion, but constantly moving by shaking back and forth, or by twisting, even thought hey stay in the same place.

8. Types of Chemical Bonds
An ionic bond is formed when metals react with nonmetals, electrons are transferred from the metals to the nonmetals.
When two or more nonmetals form compounds, they share electrons through covalent bonds. These compounds are called covalent compounds.
One way that two or more atoms can combine is to form a molecule.
Compound can have very different properties from the elements that make up that compound
Ex. Table Salt is safe to eat, the individual elements that go into making it are poisonous

9. Chemical Formulas
Chemical formulas use element symbols from the periodic table and numerical subscripts to depict the name and number of atoms of each element in the compound.
One way that two or more atoms can combine is to form a molecule.
Compound can have very different properties from the elements that make up that compound
Ex. Table Salt is safe to eat, the individual elements that go into making it are poisonous

10. Chemical Formulas
In a chemical formula, the numbers as subscripts show how many of each kind of atom are in the compound.
One way that two or more atoms can combine is to form a molecule.
Compound can have very different properties from the elements that make up that compound
Ex. Table Salt is safe to eat, the individual elements that go into making it are poisonous

11. Chemical Formulas
The subscript is written to the lower right of the element symbol.
If no subscript is written, only one atom of that element is part of the compound.
One way that two or more atoms can combine is to form a molecule.
Compound can have very different properties from the elements that make up that compound
Ex. Table Salt is safe to eat, the individual elements that go into making it are poisonous

12. Diatomic Molecules
N2, O2, F2, Cl2, Br2, I2, and H2 are diatomic molecules where all of the atoms of the molecule are the same element.
One way that two or more atoms can combine is to form a molecule.
Compound can have very different properties from the elements that make up that compound
Ex. Table Salt is safe to eat, the individual elements that go into making it are poisonous

13. Ionic Bonds
Ionic bonds are formed when metals and nonmetals chemically bond to form a new substance.
In ionic bonds, electrons are transferred from the metals to the nonmetals.
Mg N
NONMETAL
METAL 3 2
SUBSCRIPTS

14. Covalent Bonds
Covalent bonds are formed when nonmetals bond with other nonmetals.
In covalent bonds, electrons are shared.