Periodic Table of the Elements A Chemist’s “Cheat Sheet”

Development of the Periodic Table Dmitri Mendeleev – “Father of the Periodic Table” Russian Chemist who developed the 1st periodic table in the late 1800’s

Mendeleev’s First Table (1872) Elements were arranged according to increasing atomic mass Knew other elements existed and left spaces for them

An Improved Periodic Table Henry Moseley - British scientist who improved Mendeleev’s table (1911) Arranged the elements by increasing atomic number Killed in WWI at age 28

How it all fits together

Modern Periodic Table Glenn Seaborg (1912-1999)- American scientist Who arranged modern table in 1941 Placed the lanthanide/actinide series at the bottom of the table Discovered elements 94 to 102 In 1951 was awarded the Nobel Prize in chemistry Element 106 named in his honor

Periodic Trends Elements are arranged into horizontal rows called PERIODS Elements within a period have the same number of energy levels 1 energy level 2 energy levels 3 energy levels 7 energy levels 6 energy levels 5 energy levels 4 energy levels

Elements are arranged in vertical columns called a GROUP or FAMILY Elements in the same family have the same number of valence electrons and share similar CHEMICAL properties 4 valence electrons 6 valence electrons 2 valence electrons 1 valence electron 3 valence electrons 5 valence electrons 7 valence electrons (except He but all have full outer shells) 8 valence electrons

Electrons VALENCE ELECTRONS - found in the outermost energy level Determine an element’s chemical properties If the atom has a full outer shell, it is NON-REACTIVE!! Which group of elements is non-reactive? Noble gases

Periodic Trends N O R E A C T I V

Metals and Non-Metals

Metal Properties Shiny solids Ductile (able to be stretched) Malleable (able to be shaped) Good conductors of heat and electricity

Nonmetal Properties May be solids, liquids or gases Dull, brittle solids Poor conductors of heat and electricity

Metalloid Properties Nonmetals with properties of both metals and non-metals Weak conductors of heat and electricity Solids that can be shiny or dull Ductile and malleable

Families of Elements Alkali Metals Group 1, highly reactive, 1 valence electron Explosive with water

Families of Elements Alkaline Earth Metals Group 2, reactive, 2 valence electrons Hard and shiny, high melting points

Families of Elements Transition Metals Group 3-12 Complex electron arrangements

Families of Elements Halogens Group 17, highly reactive, 7 valence electrons

Families of Elements Noble Gases Group 18, full outer shells (2 in He and 8 in others) NON-REACTIVE

Families of Elements Rare Earth Elements Group 3, Period 6 and 7 Special group of transition metals

Families of Elements Metalloids Non-metal elements that are conductors of heat and electricity

ELEMENTS!!!!!!!! Want to hear a cool song????