1. Introduction to the Periodic Table
History and Properties

2. Words to Know! Period Group (or family) Valence electrons (group #)
horizontal row on the periodic table
Group (or family)
vertical column on the periodic table
Elements in families have similar properties
Valence electrons (group #)
Electrons in the outermost shell of an element
Inert
non-reactive (group18)

3. Words to Know! Luster Ductile Malleable Octet shiny
can be stretched into thin wires
Malleable
can be pounded into thin sheets
Octet
rule saying 8 electrons is “full”
H and He just need 2 e- (only one shell)

4. History of the Periodic Table
Dmitri Mendeleev
“Father of the Period Table”
Arranged his version based on
Density
Chemical Properties
Atomic Mass
Henry Moseley
Atomic Number
Crash Course Chemistry Video

5. Metals Alkali metals Group 1 (not including hydrogen)
Alkaline Earth metals
Group 2
Transition metals
Group 3 – 12
Inner Transition metals
Lanthanide and Actinide series

6. Properties of Metals Good conductors of heat & electricity
Lustrous (shiny)
Ductile
Malleable

7. Nonmetals Halogens Group 17 Noble Gases Group 18 Other nonmetals
carbon, nitrogen, oxygen, phosphorus, sulfur, selenium
Hydrogen is also a nonmetal!

8. Properties of Nonmetals
Poor conductors of heat & electricity
Dull (not shiny)
Solids are brittle and break easily (not malleable or ductile)
Many are gases.

9. Possess some properties of metals and some of nonmetals.
Metalloids
Possess some properties of metals and some of nonmetals.
Ductile and malleable
Conduct heat & electricity
but not as well as metals
Solids
Can be shiny or dull
B, Si, Ge, As, Sb, & Te
boron (B), silicon(Si), germanium(Ge), arsenic(As), antimony(Sb) and tellurium(Te).
Most common: B, Si, Ge, As, Sb, Te, & Po
Typical metalloids have a metallic appearance but they are brittle and only fair conductors of electricity. Chemically, they mostly behave as (weak) nonmetals. They can form alloys with metals. Most of their other physical and chemical properties are intermediate in nature. Metalloids are usually too brittle to have any structural uses. They and their compounds are used in alloys, biological agents, flame retardants, glasses, optical storage and optoelectronics, pyrotechnics, semiconductors and electronics. The electrical properties of silicon and germanium enabled the establishment of the semiconductor industry in the 1950s and the development ofsolid-state electronics from the early 1960s.

10. Alkali Metals Group 1 1 valence electron Soft & silvery
Conduct electricity
VERY reactive (esp. w/ water)
Never found as free elements in nature
Image:

11. Alkaline Earth Metals Group 2 2 valence electrons White & malleable
Conduct electricity
Not found uncombined in nature
Reactive, but less than Alkali metals

12. Transition Metals Groups 3-12 # of valence electrons vary
Heavier metals
Ductile
Highly malleable
Good conductors of heat & electricity
High melting and boiling points
Some used for jewelry

13. Halogens Group 17 7 valence electrons All are nonmetals Very reactive
Come naturally in pairs
diatomic molecules
Often bonded with elements from Group 1
compounds are called halides

14. Noble Gases ((AKA Inert Gases))
Group 18
Nonmetals
Exist only as gases
8 valence electrons
Full Outer Shell (Octet)
Helium only has 2 in its outer shell
INERT

15. New assignment How do you find the number of Protons in an element?
How do you find the number of Electrons?
What about the Number of neutrons?

16. New assignment How do you find the number of Protons in an element?
Atomic # = Protons #
How do you find the number of Electrons?
Protons # = Electrons #
What about the Number of neutrons?
Atomic Mass - # of Protons

17. Examples
Carbon p(+) e(-) N(+/-)
Potassium p(+) e(-) N(+/-)

18. Your turn, Do elements 1-20 Element Protons Electrons Neutrons
Valence e- H He Li Be B C N

19. Who am I? Find the element’s identity and characteristics Element
Protons
Electrons
Neutrons
Valence e- 27 7 21 4 20 9 2

20. WARM UP 9/26 Determine the following properties of each Element
Protons
Electrons
Neutrons
Atomic mass 12 8 16
35.45 10 3
12.011

21. How to Find Average Atomic Mass
Average atomic mass is not a direct measurement of a single atom. Instead, it is the average mass per atom for a typical sample of a given element.

22. Understand Isotopes and Atomic Mass
Most elements can naturally occur in multiple forms, or isotopes. The only difference between two isotopes of the same element is the number of neutrons per atom, which affects the atom's mass.

23. Example
For example, the element silver (Ag) has two naturally occurring isotopes: Ag-107 and Ag-109 (or 107Ag and 109Ag).[2] Isotopes are named after the "mass number," or the sum of protons and neutrons in one atom.[3] This means Ag-109 has two more neutrons per atom than Ag-107, giving it slightly more mass.

24. Find out the atomic mass of each Isotope

25. Find out the abundance of each isotope
The abundance tells you how common the isotope is, as a percentage of all atoms of the element.
The abundances of all isotopes should add up to 100% 

26. Then find the abundance of each

27. So… How do you find the average atomic mass?
Write down the abundance of each Isotope and turn it into a decimal (move the decimal two spaces to the left) by diving the abundance by a hundred.

28. In the sample problem, the abundance figures are 51. 86 / 100 = 0
In the sample problem, the abundance figures are / 100 = 0.5186 and / 100 = 

29. Multiply the mass by the abundance of each isotope and add up all the results

30. Naturally occurring europium (Eu) consists of two isotopes was a mass of 151 and 153.  Europium-151 has an abundance of 48.03% and Europium-153 has an abundance of 51.97%.  What is the average atomic mass of europium?

31. Your turn

32. Easier way Mass x Abundance 151x 48.03= 7,252.53
add them up=15,203.94
divide by 100 =