Elements are arranged: Vertically into Groups and Families Groups / families have similar properties - such as valence electrons Horizontally Into periods (rows) Properties change from left to right

Valence Electrons Electrons in the outermost energy level, used for bonding Full set of valence electrons is 8 Octet rule (we will discuss this in a future chapter)

The group 2 atoms all have 2 electrons in their outer shells Be (Beryllium) Atom Mg (Magnesium) Atom

Soft, silvery colored metals Very reactive!!! especially with WATER http://www.lyon.edu/webdata/Users/DMcDowell/GenChem/alkalishow.html Alkali Metals- Group 1 Valence electron = 1 Soft, silvery colored metals Very reactive!!! especially with WATER Always combined with something else in nature (like in salt).

Alkaline Earth Metals- Group 2 Valence electrons = 2 Silvery-White Metals Fairly reactive Many are found in rocks in the earth’s crust

Transition Metals- Groups 3-12 Valence electrons = 1 or 2 Malleable - easily dented hammered and rolled into sheets Ductile – pulled into wires Most are good Conductors of electricity

Lanthanide Series Actinide Series F-block Inner Transition Metals- Periods 6 and 7 Lanthanide Series Actinide Series

Boron Group- Group 13 Valence electrons = 3 Reactive Solids at room temp

Carbon Group- Group 14 Valence Electrons = 4 Solids at room temp

Nitrogen Group- Group 15 Valence Electrons = 5 All solids at room temp except nitrogen

Oxygen Group- Group 16 Valence Electrons = 6 All solids except Oxygen

Halogens- Group 17 Valence Electrons = 7 Most are Poisonous Fairly reactive Used in Disinfectants Poor conductors Used in Lights

Noble Gases- Group 18 Valence Electrons = 8 They don’t generally lose or gain electrons Unreactive (inert) Gases at room temperature Used in Lights

Jellyfish lamps made with noble gases

Colors Noble Gases produce in lamp tubes: Ne (Neon): orange-red Ar (Argon): pale lavender He (Helium): pale peach Kr (Krypton): pale silver Xe (Xenon): pale, deep blue Mixtures of these gases produce blended colors

Hydrogen In a group by itself Valence Electrons = 1 Very Reactive Has properties of 2 different families

Lewis Structures or electron dot diagrams Show valence electrons around the element’s symbol Can put at most 2 electrons next to each other To draw – place 1 electron at a time around the symbol in 4 locations (top, side, bottom, other side) before doubling up until all valence e- are used.

Lewis Structures or electron dot diagrams H P Ar

Summary Quiz As you go down a family what happens? Properties change Properties stay the same Nothing What family(group) has the most reactive metals (especially in water)? Alkaline-earth metals b. Transition metals c. Alkali metals d. Halogens

3. What group of elements have 4 valence electrons? Halogens b. Transition metals c. Boron group d. Carbon group 4. What family(group) have 2 valence electrons and are fairly reactive? Alkaline-earth metals b. Transition metals c. Alkali metals d. Halogens