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The Periodic Table and Periodic Law. Objectives: AHSGE Reading 4.3 Discern organizational patterns. Other AOD C.3.2 Recognize periodic trends of elements, including the number of valence electrons, atomic size, and reactivity. Family Calendar. Periodic Law.
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The Periodic Table and Periodic Law Objectives: AHSGE Reading 4.3 Discern organizational patterns. Other AOD C.3.2 Recognize periodic trends of elements, including the number of valence electrons, atomic size, and reactivity.
Periodic Law • Dmitri Mendeleev’s periodic table had the elements arranged in order of increasing mass. • How is the modern periodic table arranged differently? • Def: There is a periodic repetition of chemical and physical properties of the elements when they are arranged by increasing atomic number
The Modern Periodic Table • What are columns called? Answer: Groups • What are horizontal rows called? Answer: Periods • Label groups and rows on your blank periodic table as instructed, or as they are labeled on pp.156-157 of your textbook, if you are absent.
The Modern Periodic Table (continued) • Representative elements: elements in the A groups (1A-8A) • AKA, “the main group” • Possess a wide range of physical and chemical properties • Transition elements: elements in the B groups (1B-8B) • A more recent numbering system (1-18) is shown in your book., but what is an advantage to using the older system?
Metals • Describe some properties of metals. • Metals: • Generally shiny • Most are solid at room temperature • Good conductors of heat and electricity • Ductile and malleable • Most group A and all group B elements are metals.
Metals (continued) • Groups 1A and 2A, EXCEPT HYROGEN, are metals. • If H is so different, why is it in groups 1A? What does it have in common with the other elements in that group? (Hint: last test) • The other elements in group 1A are called alkali metals. • Group 2A elements are alkaline earth metals.
Metals (continued) • Both groups 1A and 2A are highly reactive (1A more so). • Why would group 1A be more reactive than group 2A? Answer: Group 2A has a FILLED s orbital, but group 1A’s s orbital is only half-filled, so that electron is still looking for a partner to hook up with.
Metals (continued) • Group B elements: • Transition metals: located on the main body of the periodic table • Inner transition metals: the 2 rows located along the bottom of the periodic table
Nonmetals • Describe some properties of nonmetals. • Nonmetals: • Generally gases or brittle, dull-looking solids • Poor conductors of heat or electricity • The ONLY nonmetal that is a liquid at room temperature is bromine. • Located in the upper right portion of the periodic table
Nonmetals (continued) • Halogens: Group 7A elements; highly reactive • Noble gases: Group 8A; extremely Unreactive. • Why are group 8A elements unreactive? Answer: Their outer valence shell is filled, so they have no need to pair up with anyone else.
Metalloids • Have properties of both metals and nonmetals. • Stair-step down from boron to astatine and germanium to polonium. • They separate the metals and nonmetals on the periodic table.
Assignments • Color-code the metals, nonmetals, and metalloids on your blank periodic table. • Complete Study Guide for Content Mastery, p.32 (18-29)