C HAPTER 4 Section 3 Families of Elements p. 120

O BJECTIVES Analyze the properties of the different families of elements Electron Configuration

I. How are elements classified? Classified by properties into groups called Families A. Metals 1. Largest family of the periodic table 2. Usually shiny 3. Conduct heat and electricity well B. Non-metals 1. On the right side of the periodic table except Hydrogen 2. Conduct heat and electricity poorly 3. Most are gases at room temperature C. Metalloids (Semiconductors)

II. Metals A. Group 1 (IA) – Alkali metals (very reactive) 1. One valence electron – bond very easily 2. Not found in nature just as elements by themselves (very soft) 3. Reacts violently with water – must be stored in oil B. Group 2 (IIA) – Alkaline-earth metals 1. Two valence electrons – still bond easily 2. Calcium- makes shells of sea animals (ex- coral reefs) – eventually limestone 3. Magnesium- lightest structural metal

C. Groups 3-12 (IIIB-IIB) – Transition Metals 1. Much less reactive 2. Conducts electricity and heat well due to type of bonding 3. Can form many different ions 4. Technetium and promethium- synthetic elements 5. Some are radioactive- nucleus is decaying to form different elements

III. Nonmetals (Groups and some 13-16) except hydrogen A. Oxygen, carbon, nitrogen- most plentiful elements on Earth B. Halogens (Group 17)- very reactive, protect from bacteria, can be poisonous C. Noble gases (Group 18) 1. Are inert – non-reactive 2. Exist as single atoms not molecules 3. Because s and p orbitals are full they do not create ions

IV. Semiconductors (Metalloids) A. On the stair step – boron, silicon, germanium, arsenic, antimony, tellurium B. Have some properties of metals- conduct under certain conditions C. Silicon is the most familiar – 28% of earth’s crust, computer chips are made from it

C LASS W ORK In groups of 3, students are to create a periodic table of students in the class. Grouped according to characteristics, each student will have one box. Your groupings must be unique to the class. Students must interview the other students to get the table completed. Use the colored pencils to color code your periodic tables by family

H OMEWORK Class Periodic Table