The Periodic Table I. History of the Periodic Table Mendeleev Mosely
A. Dmitri Mendeleev Dmitri Mendeleev (1869, Russian) Organized elements by increasing atomic mass. Predicted the existence of undiscovered elements.
B. Henry Mosely Henry Mosely (1913, British) Organized elements by increasing atomic number. Fixed problems in Mendeleev’s arrangement.
The Periodic Table II. Organization Metallic Character Rows & Columns Table Sections
A. Metallic Character Metals Nonmetals Metalloids
B. Table Sections Representative Elements Transition Metals Inner Transition Metals
B. Table Sections Lanthanides - part of period 6 Actinides - part of period 7 Overall Configuration
C. Columns & Rows Group (Family) Period
Alkali Metals Soft and shiny React violently with water 1 valence electron Forms ions with +1 charge 1+ is oxidation number
Alkaline Earth Metals Have 2 valence electrons Form ions with +2 charge Less reactive than alkali metals 2+ is oxidation number
Halogens Has 7 valence electrons Forms ions with -1 charge 1- is oxidation number Very reactive
Noble Gases Have full octet (8) of valence electrons (except Helium which has 2) Called “inert gases” because they don’t tend to react
The Periodic Table III. Periodic Trends Terms Periodic Trends Dot Diagrams
Periodic Law Properties of elements repeat periodically when the elements are arranged by increasing atomic number. A. Terms
Valence Electrons e - in the outermost energy level Atomic Radius First Ionization Energy energy required to remove an e - from a neutral atom
B. Periodic Trends Atomic Radius Increases to the LEFT and DOWN.
B. Periodic Trends First Ionization Energy Increases to the RIGHT and UP.
B. Periodic Trends Which atom has the larger radius? BeorBa CaorBr Ba Ca
B. Periodic Trends Which atom has the higher 1st I.E.? NorBi BaorNe N Ne
B. Periodic Trends Group # = # of valence e - (except He) Families have similar reactivity. Period # = # of energy levels 1A 2A 3A 4A 5A 6A 7A 8A
C. Dot Diagrams Dots represent the valence e -. EX: Sodium EX: Chlorine