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Chapter 3: Introduction to the Periodic Table. Section 3.2: Using the Periodic Table.
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Chapter 3: Introduction to the Periodic Table Section 3.2: Using the Periodic Table
Objectives: Relate an element’s valence electron structure to its position in the periodic table, Use the periodic table to classify an element as a metal, nonmetal or metalloid, Compare the properties of metals, nonmetals or metalloids
Arrangement • Elements are arranged according to atomic number • Atomic number = electrons/ protons • PERIOD- horizontal row in the table • GROUP (family)- vertical column in the table • For elements in group 1 and 2: The group number equals the number of valence electrons • For elements in groups 13, 14, 15, 16, 17, 18: The second digit in the group number is equal to the number of valence electrons
Arrangement Elements in the same group have the same number of valence electrons, similar properties http://www.ptable.com/ • Alkali metals are elements in Group 1 (most reactive metals) • Alkaline earth metals are elements in Group 2 • Halogens are elements in Group 17 (most reactive nonmetals) • NOBLE GASES: Elements in Group 18 Maximum 8 valence electron- unreactive – octet rule
Physical states of elements • Most elements are solid, only 2 elements are liquid (Br, Hg) • Gaseous elements are in the upper-right corner of the table, except hydrogen • Some elements are not found in nature- synthetic elements are produced artificially Include: Element 43, Technetium All elements after element 92, Uranium
Classifying Elements • Majority of elements are metals- left side and center • Nonmetals- upper-right-hand corner • Metalloids- along the boundary between metals and nonmetals http://www.ptable.com/
METALS • Metals have 1, 2, or 3 valence electrons - except Lead, Bismuth, and Tin • Strong and durable • Have luster, conduct heat and electricity • Usually bend without breaking • All metals are solid at room temp, except Hg • Good conductors
METALS TRANSITION ELEMENTS: Elements in groups 3 through 12 of the periodic table • Predicting behavior and properties of transition metals is complicated due to the atomic structure of these elements Inner Transition Elements • Placed below the periodic table- proper position would make table too wide
METALS • LANTHANIDES- first series of inner transition elements Elements 58-71, also called rare earth elements • ACTINIDES- second series of inner transition elements Elements 90-103, all are radioactive
NONMETALS • Poor conductors of electricity and heat, and are brittle as solids • Many are gases at room temperature, lower melting points than metals • Nonmetals have 5, 6, 7, 8 valence electrons, except Carbon
Metals and Nonmetals • Atomic Structure • Metals • Valence electrons are loosely bound to the positive nucleus • Electrons are free to move in the solid metal and are easily lost • This motion allows for their good conductivity
METALLOIDS • Elements that have chemical and physical properties of metals and nonmetals Ex: Silicon, Germanium, Arsenic • Form border between metals and nonmetals • Some metalloids are semiconductors.
METALLOIDS SEMICONDUCTOR: Element that does not conduct electricity as well as metal, but does conduct slightly better than a nonmetal • Valence electrons in nonmetals and metalloids are tightly held to the nucleus • In reactions, nonmetals tend to share or gain electrons • http://www.youtube.com/watch?v=u3GdpbKTPQQ&safety_mode=true&persist_safety_mode=1&safe=active
METALLOIDS Semiconductor uses: • Used in electronic devices (circuits): TV, computers, calculators • Semiconductors are “doped” with a small amount of another element → allows the movement of electrons → produces electricity • p-type semiconductor- creates “holes” that allows electrons to move in and out • n- type semiconductor- extra electrons present are free to move
METALLOIDS Transistors, diodes, and other semiconductors are incorporated onto thin slices of silicon (chip) to form integrated circuits → growth of computer technology
MATCHING CONCEPTS Match words or phrases in column 1 with words or phrases in column 2. It is possible to have multiple connections…find as many as you can! BUT, be able to justify the connection! COLUMN 1 COLUMN 2 • Conductivity Inner Transition Element • Group Family • Nonmetal State of Matter • Mendeleev Semiconductor • Energy Level Metal • Silver Alkali Metal • Liquid Mercury • Lanthanides Bromine • Sodium Noble Gas • Alkaline Earth Metal Group 2 • Group 18 Periodicity • Halley’s Comet Group 1 • Solid Magnesium • Metalloid Actinide • 7 Energy Levels Gas • 1 Valence Electron Period