The student will:

identify parts of periodic chart

explain periodic law in relationship with chemical reactions

calculate trends of periodic chart

calculate trends according to location of element on periodic chart

Chapter 5 p.123 Periodic Table

Periodic means = Repeating pattern

Dimitri Mendeleev Russian chemist,

1866, published in 1869

Mendeleev- discovered pattern by chemical properties---- left empty spaces…

42 yrs later …Henry Mosely English chemist 1911

Modern definition of Atomic# = modern organization of Periodic Table.

http://www.youtube.com/watch?v=AGZ20OrmYBs&feature=related

• PT divided into two sections • Metals / non-metals via stair steps • Metals on the left of stairs

• Metals conduct electricity & heat • Non-metals on the right of stairs

• Non-metals do not conduct electricity very well and heat only slightly. Most are gases and powders.

• Metalloids • Elements touching the stair steps

» Exclude Aluminum

• Properties of both, “can’t make up their mind”• “Semi-conductors” ….used in computer chips

• Elements going sideways period• Elements going down group or family• Period numbers down side tell largest occupied energy level. • Group numbers across the top tell number of valence electrons.

• there are some deviations • transition elements, the group # equal the sum of the s & d electrons. *

Important Concept Periodic Law ::::::

Groups or families exhibit same characteristics.

• Note: outer valence electrons determine chemical properties SO…..all elements in a group or family will have similar chemical properties.

• Official way to say it : The physical & chemical properties of elements are a periodic function of their atomic number.

HYDROGEN :doesn’t share same properties as group 1

is placed above group 1 because it does have the 1s1 orbital filled.

• Group 1 Alkali Metals » Very reactive, explosive, does not exist

pure in nature• Group 2 Alkaline-Earth Metals

» Very reactive but not as active as group 1 does not exist pure in nature

• Group 3-12 Transition Metals » Less reactive, some not reactive, good

conductors of electricity, heat

Group 17 Halogens Very reactive, gasesGroup 18 Noble Gases Not reactive, inert,

LanthanidesExtremely similar,

tedious to distinctionActinides

Radioactive, short life

• Diatomic Molecules = • 2 atoms of same element chemically combine in nature

N2 O2 F2 Cl2 Br2 I2 H2

When writing these you must write them as diatomic !!!!! Or it will be wrong!!!!

Carbon

3 forms called allotropes p. 626 in book

**Allotrope= same element different structural form

l. Diamond….. Atoms in a pyramid

2. Graphite ….. Atoms in layers. pencil

3. Fullerenes….Atoms in a sphere…coal

periodic table based on carbon-12

• Alloys:– Brass = Cu + Zn– Bronze = Cu + Sn– Sterling Silver = Cu + Ag – Pewter = Cu + Sn + Sb

• Gold:• 100% gold = 24 karat • 92% gold = 22 karat….8% copper• 58% gold = 14 karat …42% copper• 50% gold = 12 karat ….50% copper

• What property does copper add to the gold?• What makes your skin turn green with fake gold?

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