Chemistry Chapter 6 The Periodic Table

Developed by Dimitri Mendeleev in 1869 Arranges the elements by similarities in their chemical properties Each element has a unique symbol and atomic number

The 1 st Periodic Table

Metals v. Nonmetals

Example Classify the following elements as metals or nonmentals. BromineTungsten MagnesiumPhosphorus MercuryLithium HydrogenNeon

Electron Configurations The periodic table is arranged by electron configurations Unknown to Mendeleev and Moseley Elements with the same electron configuration in the outer energy level are in the same groups

Transition Metals These are the d-block and f-block metals Form colored compounds Typically are more dense, and have higher melting and boiling points than s-block metals

Noble Gases The last group discovered because of inertness In 1895 argon was successfully isolated from air Soon after other noble gases were isolated and they were added to the periodic table

Alkali Metals All highly reactive and are never found in elemental form in nature Soft metals React readily with water to form bases All electron configurations end with ns 1

Alkaline Earth Metals Much less reactive than alkali metals Soft metals Can be made to react with water to form bases All electron configurations end with ns 2

Halogens Most reactive nonmetals Are all found as diatomic molecules in their pure form Contain gases, a liquid, and solids All electron configurations end with ns 2 np 5

Example Classify the following elements as alkali metals, alkaline earth metals, transition metals, halogens, or noble gases. Bromine Magnesium Mercury Lithium Neon Tungsten Halogen Alkaline Earth Metal Transition Metal Alkali Metal Noble Gas Transition Metal