1. Types of Matter Key Idea #6
Elements and compounds are both made of atoms and can be identified by a unique set of physical and chemical properties.

2. Elements are chemical substances that make up all other substances.
are made up of only one kind of atom.
can’t be broken down into other substances by any physical or chemical means.
are organized on the Periodic Table in families.

3. Examples of Common Elements: Copper Helium Aluminum
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4. Atoms are the smallest particle that makes up an element.
have a core called a nucleus.
are so small, models are used to understand them.
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5. Atoms are made up of
protons and neutrons - found in the nucleus of an atom.
electrons - found in a cloud around the nucleus.
Protons: positive (+) charge
Neutrons: neutral ( ) charge
Electrons: negative (-) charge

6. Atomic Number Atomic Number Atomic Mass
a unique property that identifies an element
tells how many protons are in an element’s atoms
also tells the number of electrons that surround the nucleus
The number of electrons is always equal to the number of protons
Atomic Mass
The average mass of one atom of an element.
Measured in atomic mass units (amu’s)

8. Elements are different from each other because of the number of protons, neutrons, and electrons their atoms contain.
Element Name and atomic #
# of protons
# of neutrons
# of electrons
Average
Atomic
Mass
Atomic Weight
Average mass rounded to the nearest tenth
Mass #
Total # of protons
and neutrons
Hydrogen 1
1.0

9. Elements are different from each other because of the number of protons, neutrons, and electrons their atoms contain.
Element Name and atomic #
# of protons
# of neutrons
# of electrons
Average
Atomic
Mass
Atomic Weight
Average mass rounded to the nearest tenth
Mass #
Total # of protons
and neutrons
Hydrogen 1
1.0
Boron 5 6
10.811
10.8
11.0

10. Elements are different from each other because of the number of protons, neutrons, and electrons their atoms contain.
Element Name and atomic #
# of protons
# of neutrons
# of electrons
Average
Atomic
Mass
Atomic Weight
Average mass rounded to the nearest tenth
Mass #
Total # of protons
and neutrons
Hydrogen 1
1.0
Boron 5 6
10.811
10.8
11.0
Carbon
12.0

11. Elements are different from each other because of the number of protons, neutrons, and electrons their atoms contain.
Element Name and atomic #
# of protons
# of neutrons
# of electrons
Average
Atomic
Mass
Atomic Weight
Average mass rounded to the nearest tenth
Mass #
Total # of protons
and neutrons
Hydrogen 1
1.0
Boron 5 6
10.811
10.8
11.0
Carbon
12.0
Oxygen 8
16.0

12. Elements are different from each other because of the number of protons, neutrons, and electrons their atoms contain.
Element Name and atomic #
# of protons
# of neutrons
# of electrons
Average
Atomic
Mass
Atomic Weight
Average mass rounded to the nearest tenth
Mass #
Total # of protons
and neutrons
Hydrogen 1
1.0
Boron 5 6
10.811
10.8
11.0
Carbon
12.0
Oxygen 8
16.0
Gold 79
118
197.0

13. Element Atomic Energy Levels
Level 1: holds up to 2 electrons
Level 2: holds up to 8 electrons
Level 3: holds up to 18 electrons
Level 4: holds up to 32 electrons
Level 5: holds up to 32 electrons
Level 6: holds up to 18 electrons
Level 7: holds up to 2 electrons
In some cases an energy level will not be completely filled before electrons begin to fill the next level.

14. Francium Number of Energy Levels: 7
Number of Energy Levels: 7
First Energy Level: 2 Second Energy Level: 8 Third Energy Level: 18 Fourth Energy Level: 32 Fifth Energy Level: 18 Sixth Energy Level: 8 Seventh Energy Level: 1

15. Potassium Number of Energy Levels: 4
First Energy Level: 2 Second Energy Level: 8 Third Energy Level: 8 Fourth Energy Level: 1
Note:
The third energy level only holds 8 electrons, even though there is room for 18.

16. The Periodic Table by Energy Levels

17. Another name for energy levels is electron shells

18. The stability of an atom depends on its electron configuration.
The outermost electrons determine the chemical reactivity of the atom and are called valence electrons.

19. Model of a Silicon Atom

20. Valence Electrons
When A groups are numbered from 1 through 8, the number matches the number of Valence electrons.
A valence electron is the highest occupied energy level.
Elements have similar properties because they have the same number of valence electrons.

21. Sodium metal + Chlorine gas = Table Salt

22. Na + Cl = NaCl (table salt)
When metals and nonmetals react, valence electrons move from the metal atoms to the nonmetal atoms.

23. Elements on the periodic chart are represented by
symbols and organized by similar properties into groups
called families.
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24. Calendars are organized into
Days
Weeks
Months

25. Elements are organized into
Groups (families)
vertical columns
similar to the days of the week on a calendar
elements in a group
have similar properties
have the same number of valence electrons
Periods
horizontal rows
similar to the weeks on a calendar
elements in a period
don’t have similar properties
are arranged by increasing atomic number
have the same number of electron containing energy levels