DO NOW Take your poster out. Trade posters with someone and write down all the facts you can find in their poster. Objective: relate the number of valence electrons to groups in the periodic table and to the properties of elements in those groups.
What is a valence electron? • An electron that is in the highest occupied energy level of an atom.
Valence Electrons (continued) • The valence electrons play a key role in CHEMICAL REACTIONS. • Elements in a group have similar properties because they have the same number of valence electrons.
The Alkali Metals • Group 1A • Have a single valence electron • Extremely reactive • Reactivity increases from top to bottom • Only found in nature as compounds
The Alkaline Earth Metals • Group 2A • Have two valence electrons • Harder than metals in 1A • Magnesium and Calcium have essential biological functions • Magnesium- is at the center of chlorophyl • Calcium- keeps your bones and teeth strong
The Boron Family • Group 3A • Have 3 valence electrons • contains1 metalloid and 4 metals • ALUMINUM is the most abundant metal in Earth’s crust
The Carbon Family • Group 4A • Contains 4 valence electrons • Contains 1 nonmetal, 2 metalloids, 2 metals • Except for water, most of the compounds in your body contain carbon
The Nitrogen family • Group 5A • Contains 5 valence electrons • Wide range of physical properties • Fertilizers contain nitrogen and phosphorous
The Oxygen Family • Group 6A • Have 6 valence electrons • 3 nonmetals 2 metalloids • Oxygen is the most abundant element in Earth’s crust.
The Halogens • Group 7A • Have 7 valence electrons • Despite physical differences, the halogens have similar chemical properties • Highly reactive nonmetals
The Noble Gases • Group 8A • Helium has 2 valence electrons, all others have 8 • Colorless and odorless and extremely unreactive.
Recap • Objective: relate the number of valence electrons to groups in the periodic table and to the properties of elements in those groups. • What do the group numbers mean in relation to valence electrons.
Homework • Complete group poster • Questions 1-10 on page 153 • TEST THURSDAY!!!!