 What makes up an atom?  How would you draw a Bohr model of Nitrogen?

 Valence electrons- the outer most electrons on the Bohr model ◦ Can participate in a chemical bond  How many valence electrons are there in Nitrogen?

 On a whiteboard, draw a Bohr model for elements atomic numbers 3-10  How many valence electrons are in each one?

 Why is the atomic mass not an exact number?  Elements occur in nature as mixtures of isotopes.  Isotopes- atoms of the same element having different masses, due to varying numbers of neutrons.  Ex) Carbon-14, Uranium-235

 Each table will be given a cup of 11 different candies. Consider these candies to be different “elements”  Create a table with multiple rows and columns with the candy. There should be patterns/organization within the table *When organizing, consider what makes up the candy? What size is it? What company? etc. *Which row will have chocolate? Which row will have yellow candy?, etc.  After 5 minutes, groups will then share and explain how they arranged their table

 How did you arrange your rows?  How did you arrange your columns?  Are there any candies that would fit well to your trends?  What things did you consider when arranging your candies?

 How is the modern Periodic Table organized?  Why do the elements in a group have similar properties?

Dmitri Mendeleev: ● "Father of the Periodic Table" ● Mid-1800's ● Organized table by elements’ chemical & physical properties ● Open spots in table = undiscovered elements o Correctly predicted their properties’s o Originally only 63 elements, now there 118

Mendeleev came up with the “Periodic Law of the Elements.” Periodic Law – properties of elements change in a relationship to atomic number that repeats. ● "Periodic" = repeating pattern

Henry Mosley: ● Organized table by periods and groups. The original Periodic Table was organized horizontally by increasing mass & vertically by similar properties.

Periods - horizontal rows ● Organized by increasing atomic number Groups (also called “Families”) - vertical columns ● Organized by similar properties

Directions: 1.As you read through the presentation, color the groups of your periodic table accordingly using colored pencils. 2.Include a key that details the names of each group you colored.

 Group: 1  Properties: Soft & very reactive  # of Valence Electrons: 1 Color: dark green

 Group: 2  Properties: React with acids to produce hydrogen  # of Valence Electrons: 2 Color: light green

 Group: 17  Properties: React with metals to form salts  # of Valence Electrons: 7 Color: yellow

 Group: 18  Properties: Non-reactive ("noble" or "inert")  # of Valence Electrons: 8 Color: red

Xenon is a noble gas that is six times more dense than air. Helium is a noble gas that is six times less dense than air.

Metals: left side of the Periodic Table ● Most of the Periodic Table (75% of all elements) STAIRCASE

Characteristics of Metals: 1.Luster (shiny solids) 2.Malleable (bendable) 3.Ductile (stretchable) 4.Conducts electricity & heat well STAIRCASE

Metalloids: touching the “staircase” on the Periodic Table ● Have properties of metals AND nonmetals STAIRCASE

Nonmetals: far right of the Periodic Table ● Most are gases at room temperature or brittle solids ● Poor conductors of electricity & heat STAIRCASE