1. Particles of Matter

2. Atoms and Molecules
The smallest particle of all matter and the basis of everything in the Universe – Atom.

3. Inside an Atom Atoms are composed of 3 basic parts:
Protons – positively (+) charged particles located in the nucleus of the atom.
Neutrons – neutrally (O) charged particles located in the nucleus of the atom.
Electrons – negatively (-) charged particles located in the orbits surrounding the nucleus.

4. Orbits
Shell Basics:
The orbits, shells, surround the nucleus and hold a specific number of electrons that are always moving.
Shells are sometimes called energy levels

5. Energy Levels Orbit 1 (K) – 2 electrons Orbit 2 (L) – 8 electrons
Orbit 3 (M) – 8 electrons
Orbit 4 (N) – 18 electrons 10 18 36

6. Scientists Behind Atoms
Democritus
Greek philosopher
Lived about 440 B.C.
He thought that there were smallest possible “pieces” of everything.
Called this smallest piece, atomos – Greek for “uncuttable”.

7. Scientists Behind Atoms
2. Dalton
British schoolteacher – 1802
Proposed the atomic theory
Theory about atoms
Dalton’s ideas form the basis of our understanding of atoms!

8. Dalton’s Conclusion about Atoms
Through experiments he concluded:
Atoms can’t be broken into smaller pieces.
All atoms in an element are exactly alike.
Atoms of different elements are different.
Atoms of two or more elements combine to form compounds.
Atoms of each element have a unique mass.
The masses of the elements in a compound are always in a constant ratio.

9. Organizing Elements Dmitri Mendeleev 1800’s, Russian scientist
Thought elements could be organized by:
Similar chemical and physical properties
Atomic mass
Bonding power

10. The First Periodic Table
1869, Mendeleev published the first periodic table of elements.
Periodic = “a regular, repeating pattern”

11. Organizing the Periodic Table
Arranged by atomic number
Groups (families):
Vertical columns down, 1-18.
Based on similar characteristics
Periods :
horizontal rows across, 1-7.
Metals
Classified based on physical properties such as:
Hardness
Shininess
Malleability – can be pounded into shape
Ductility – can be pulled or drawn into a long wire
Good conductors – transmit heat and electricity easily.
Solid at room temperature.

12. Organizing the Periodic Table
Nonmetals
Characteristics are opposite of metals:
Gas at room temperature.
Poor conductors
Dull
Brittle – break easily
Metalloids
Boarder between metals and nonmetals
Characteristics similar to both metals and nonmetals:
Varying ability to conduct electricity.
Temperature, light or impurities affect conductivity.
7. Nobel Gases
Group 18
Chemically stable and unreactive
Outer shell, valance electrons, is completely full – can’t form compounds

13. The Periodic Table 1 18 Groups 1 2 13 14 15 16 17 2 3 3 4 5 6 7 8 9 10
Key:
Metal
Metalloid
Nonmetal
Nobel Gas
The Periodic Table 1 18
Groups 1 2 13 14 15 16 17 2 3 3 4 5 6 7 8 9 10 11 12
Periods 4 5 6 7

15. Inside the Squares Each square contains: Element Name Element Symbol
Atomic Number
Number of protons in the
nucleus or electrons in the orbits of the atom (p = e-)
Atomic Mass
The number of protons + neutrons in the nucleus of the atom (p + n)

16. Atomic Number & Atomic Mass
All atoms have a specific mass that is calculated by the number of Protons and Neutrons in the nucleus of the atom.
Atomic Mass = Protons + Neutrons (p + n)
The atomic number is calculated by the number of protons in the nucleus or the number of electrons in the orbits.
Atomic Number = Protons or electrons (p = e-)
Electrically Neutral!

17. Protons, Neutrons & Electrons
Atomic Number = Protons (p = e-) Atomic Mass = Protons + Neutrons (p + n) (p=e-) (p+n) (p) (n) (e-)
Atomic Mass
Atomic Number
Element Symbol
Element Name
Element
Symbol
Atomic Number
Atomic Mass
Protons
Neutrons
Electrons +
Carbon C 6 12 6 6 6

18. Protons, Neutrons & Electrons
(p=e-) (p+n) (p) (n) (e-)
Element
Symbol
Atomic Number
Atomic Mass
Protons
Neutrons
Electrons
Helium He 4 7 14 11
Iron Fe 56 30
Copper 29 Ag
108 61 2 2 + 2 2
Nitrogen N 7 7 23 11 12 11
Sodium Na 26 26 26 Cu 64 35 29 47
Silver 47 47

19. Atomic Structure Nitrogen: Oxygen: 7 8 7 8 7 14 8 16 7 8 7 8 7 8
Atomic Number: ________
Protons: _____
Neutrons: _____
Electrons: _____
Oxygen:
Atomic Number: ________
Protons: _____
Neutrons: _____
Electrons: _____ 7 8 7 8 7
Atomic Mass: 14 8
Atomic Mass: 16 7 8
p =
n = 7
p =
n = 8 7 8

20. Atomic Structure Sodium: Hydrogen: Atomic Number: ________
Protons: _____
Neutrons: _____
Electrons: _____
Hydrogen:
Atomic Number: ________
Protons: _____
Neutrons: _____
Electrons: _____ 11 1 11 12
Atomic Mass: 23 1 1 11
Atomic Mass: 1
p =
n = 1
p =
n = 11 12