Periodic Table

The First Periodic Table of Elements Discovered by Dmitri Mendeleev Only had 63 naturally occurring elements to work with Organized the table by Increasing Atomic Mass Left places for undiscovered elements

All Modern New The Modern Periodic Table Organized by Henry Mosley Arranged by Increasing Atomic Numbers

Valence Electrons Electrons found in the last shell, orbital or energy level The Code: 1, 2, 3, 4, 5, 6, 7, 8 Look above the column for the number paired with “A”

Oxidation Number Number of electrons that the element will gain or lose to become stable. Code: –+1,+2, +3, +/-4, -3, -2,-1,0

Parts of the Periodic Table Rows – Periods (arranged by # of shells) Columns- Families or Groups (arranged by the valence electrons and properties)

Periods How many? 7 Why are they placed here? They have the same # of shells, orbitals or energy levels

Families or Groups How many columns? 18 Why are elements placed here? They have the same chemical properties and valence #

Classification of Elements 1. Metals 2. Nonmetals 3. Metalloids

Metal Properties  Shiny  High Melting Point  Ductile (form into a wire)  Malleable (hammer into a shape)  Reacts with acid  Good conductors  Found on the left hand side of the table  Most of the elements are metals  Francium—most reactive metal

Nonmetal Properties  Dull  Low melting point  Brittle  Poor conductors  Found on the right hand side of the table.  Gas at room temp  Fluorine—most reactive nonmetal

Metalloids  Both characteristics of Metals and Nonmetals  Found on the stair step line on the table  Left side – metal qualities  Right side – nonmetal qualities

Metalloids

Periodic Properties Electron Arrangement –Table is arranged by increasing atomic number Atomic Size –decreases from left to right (Gravity pulls in the electrons towards the center) –Increases in size from top to bottom (more shells) Reactivity –The left side is more unstable than the right side. Metallic Properties –Left to right – metals to nonmetals

All in the Family Families of the Periodic Table 1. Alkali Metals 2. Alkaline Earth Metals 3. Transitional Metals 4. Boron Family 5. Carbon Family 6. Nitrogen Family 7. Oxygen Family 8. Halogen Family 9. Noble Gases Family

Families Alkali Metals 1A  1 valence electron  Violent reaction to water  Francium is the most reactive metal Alkaline Earth Metals 2A  2 valence electrons  Mg and Ca (clays and laxatives)

Families Transitional Metals 3B – 12B 3B – 12B  Vary in Valence #  Brightly colored  Oxides – combine with oxygen

Families Boron 3A  3 valence electrons  Al: only metal on the stair step line Carbon 4A  Carbon is the element of life  4 valence electrons

Families Nitrogen 5A  5 Valence electrons  N: 78% of air  Main components of fertilizers Oxygen 6A  6 Valence electrons  O: reacts with All elements and most abundant element in Earth’s crust.

Families Halogen 7A  7 Valence electrons  Fluorine: most reactive nonmetal  Salt formers  Reactive with metals Noble Gases 8A  Inert Gases  Most stable  No reactivity  All shells are full  8 valence electrons

Drawing Bohr’s Models # of energy levels = # row element is in (period #) # of electrons in outer shell = valence electron (group #) Orbital one has a max of 2 electrons All other orbitals have a max of 8 electrons Practice He Ne N