Post on 06-Jan-2018
description
transcript
Chemistry
Chapter 6The Periodic Table
The Periodic Table
• Developed by DimitriMendeleev in 1869
• Arranges the elements by similarities in their chemicalproperties
• Each element has a unique symbol and atomic number
The 1st Periodic Table
Metals v. Nonmetals
Example
Classify the following elements as metals or nonmentals.Bromine TungstenMagnesium PhosphorusMercury LithiumHydrogen Neon
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
ns1
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
ns2
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
ns2np5
Example
Classify the following elements as alkali metals, alkaline earth metals, transition metals, halogens, or noble gases.BromineMagnesiumMercuryLithium NeonTungsten
HalogenAlkaline Earth MetalTransition MetalAlkali MetalNoble GasTransition Metal