The Periodic Table Sec 1 How are Elements Organized Sec 2 Tour of the Periodic Table Sec 3 Trends in the periodic Table

Sec 1 How are Elements Organized Describe the historical development of the periodic table. Describe the organization of the modern periodic table according to the periodic law.

History of the Periodic Table John Newlands was the first notice a pattern. He placed the elements in a table according to atomic mass and properties. (1865) He noticed the pattern repeated every eight elements He called this the law of octaves

History of the Periodic Table Dmitri Mendeleev was the first to develop an accepted periodic table of the 63 known elements at the time.(1869) Ordered elements by atomic mass, started new rows when chemical properties repeated.

History of the Table Mendeleev left blanks in the table where no known elements fit his pattern. He predicted that the blanks would be for elements that were yet to be discovered. This turned out to be true, that is why he is created with the first table.

History of the table Mendeleev’s table was flawed Some elements had to be rearranged due to their properties not matching up.

History of the Table 40 years after Mendeleev, Henry Mosely arranged elements by atomic number thus correcting Mendeleev’s flaw

Periodic Law When elements are placed in order by atomic number, elements in the same group will have the same properties. This is due to valence electrons, or outer electrons. Valence electrons are the electrons involved in chemical bonding.

Sec 2 Tour of the Periodic Table Locate element families and describe their chemical/physical properties. Relate their properties to electron configurations

Main Group Elements Include the S and P Blocks of the periodic table. There are 4 groups within the main group elements.

Alkali Metals Include elements in group 1. Highly reactive with water. So reactive they are never found in nature as pure elements.

Alkaline Earth Metals Includes the elements in group 2 Slightly less reactive than alkali metals Reactive enough that they do not exist in the single element form.

Halogens Includes the elements in group 17 Most reactive group of nonmetals

Noble Gases Group 18 Are unreactive elements Only exist as single atoms.

Hydrogen Does not fall with in any of the other groups in the periodic table. Is considered to be in a class by itself

Transition Metals Includes all elements in group 3-12. Less reactive than alkali, alkaline-earth, and halogens. Some transition metals do not form compounds, however most do.

Sec 3 Trends in the Periodic Table I can Describe trends in the peridioc table and relate them to atomic structure of elements: Ionization Energy Atomic Radius Electronegativity Ionic Size Electron Affinity Melting and Boiling Points

Ionization Energy The energy required to remove an electron Decreases as you move down a group and increases as you move across a period Electron Shielding-inner electrons weaken the attraction of outer electrons to the nucleus, thus making it easier for outer electrons to be removed

Atomic Radius Is the size of an atom Increases as you move down a group and decreases as you move across a period Bond Radius- half the distance from center to center of to like atoms bonded together.

Electronegativity Ability of an atom to attract electrons Decreases as you move down a group and increases as you move across a period.