1. The Periodic Table

2. What is the periodic table?
A table where all of the known elements are arranged according to atomic #
Mendeleev-first p. table arranged by atomic mass
Moseley-out table arranged by atomic #

3. Which way does a group go?
Groups – vertical column (also known as a family) of elements with similar properties
The column dictates the number of valence electrons an atom has
Numbered 1-18 (Most important 1,2,13-18)
Valence Electron – electron in the outer most energy level

4. Which way does a period go?
Period – horizontal row of elements that contain increasing numbers of protons and electrons as you move right across table
Each row in the period ends when the outer energy level is filled
Numbered 1-7

5. How do you know how many electrons are in the outer energy level?
The number of valence electrons tells you how many electrons are in the outermost energy level. This is dictated by which group the element is in on the table.
Group 1 = 1 valence electron
Group 2 = 2 valence electron
Group 13 = 3 valence electron
Group 14 = 4 valence electron
Group 15 = 5 valence electron
Group 16 = 6 valence electron
Group 17 = 7 valence electron
Group 18 = 8 valence electron = FULL SHELL = OCTET

6. Electron Dot Diagrams Use the element Symbol & Valence Electrons
Place one dot on each side of imaginary square around symbol until there is one on each side and then partner if needed
There should never be more than two dots per side of square
Maximum = 8 electrons (2 per side)
Al Ne Li

7. Exit Ticket
Which elements are the most reactive?