1. Elements and the Periodic Table

2. Vocabulary Mendeleev – said elements are periodic
Periodic Law – elements have a regular repeating pattern based on their atomic #
Atomic # – # of protons
Valence electrons – electrons in the outermost electron shell (valence shell)

3. The Periodic Table Arranged in increasing atomic #
Period – horizontal rows
Groups – vertical columns; in each group, elements have some similar properties

4. The Periodic Table of Elements
Metals
Metalloids
Nonmetals

5. Metals Most elements are metals
Found to the left of the periodic table
Most have few electrons in their outermost energy level
Most are solid at room temperature
Good conductors (allow heat and electricity to pass through)
Shiny
Malleable (can be flattened without shattering).
Ductile (can be drawn into wires).

6. Nonmetals Found to the right of the periodic table. Poor conductors
Have almost complete valence energy levels.
More than half are gases at room temperature.
Have opposite properties of metals.
Poor conductors
Dull
Brittle & break easy.
They are not malleable or ductile because they break easy.

7. Metalloids
They are the elements that border the zigzag line on the periodic table (except aluminum).
They have about a half complete valence or outer energy level.
They have some properties of metals and some properties of nonmetals.
Example: Tellurium is shiny but it is brittle.

8. Periods tell how many energy levels an element has

9. Groups tell how many valence electrons an element has

10. Group 1 – The Alkali Metals
Very Reactive!!!
1 electron in valence shell
all metals
Soft, silver-colored, shiny, low density
Li, Na, K, Rb, Cs, Fr

11. Group 18 – Noble (Inert) Gases
Unreactive!!!
They are stable!
8 electrons in the valence shell (2 for Helium)
Colorless, odorless gases at room temp.
He, Ne, Ar, Kr, Xe, Rn
Everyone wants to be like them!

12. Hydrogen stands alone!!!!!! Hydrogen is reactive!!!!!!!!!!!!!
Has 1 electron in its outer shell
Colorless, odorless gas at room temperature
Reacts explosively with oxygen