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WEdnesday 3/23/11 Bell Ringer Pick up the notes off the front demo table, turn in the Periodic Table Activity from the last two days & the extra credit Try to answer this question on the back: If you were an alchemist (first type of chemist) and were given a set of substances like the one up front, how would you classify and characterize these? What experiments could you do to determine properties?. Assignment 1.Bell Ringer 2.Periodic Table Notes HOMEWORK: Review your notes I can…. Identify the electron configuration of an element and the characteristics of that element
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Alchemy !! Alchemy !!
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Reading the Periodic Table
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A. Mendeleev Dmitri Mendeleev (1869, Russian) Organized elements by increasing atomic mass. Elements with similar properties were grouped together. There were some discrepancies.
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Mendeleev’s Periodic Table Dmitri Mendeleev
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Modern Russian Table
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A Spiral Periodic Table
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“Mayan” Periodic Table
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B. Moseley Henry Moseley (1913, British) Organized elements by increasing atomic number. Resolved discrepancies in Mendeleev’s arrangement.
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The Periodic Table Period Group or family Period Group or Family
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Rows The horizontal rows of the periodic table are called periods. Elements in a period are not alike in properties. The first element in a period is usually an active solid, and the last element in a period is always an inactive gas.
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Rows Atomic size (number of protons) increases from left to right across a period. Atomic mass (number of protons + neutrons) increases from left to right across a period. Metals on left, nonmetals on right
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Columns The vertical (up and down) columns of the periodic table (there are 18) are called groups or families. Elements in the same group or family have similar characteristics or properties.
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Metals Nonmetals Metalloids Metallic Character Metallic Character
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Properties of Metals Metals are good conductors of heat and electricity Metals are malleable (flattened & molded) Metals are ductile (can be rolled & pulled into wire) Almost all metals have luster (shine)
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Examples of Metals Potassium, K reacts with water and must be stored in kerosene Zinc, Zn, is more stable than potassium Copper, Cu, is a relatively soft metal, and a very good electrical conductor. Mercury, Hg, is the only metal that exists as a liquid at room temperature
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Examples of Nonmetals Sulfur, S, was once known as “brimstone” Microspheres of phosphorus, P, a reactive nonmetal Graphite is not the only pure form of carbon, C. Diamond is also carbon; the color comes from impurities caught within the crystal structure
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Properties of Metalloids Metalloids straddle the border between metals and nonmetals on the periodic table. They have properties of both metals and nonmetals. Metalloids are more brittle than metals, less brittle than most nonmetallic solids Metalloids are semiconductors of electricity Some metalloids possess metallic luster
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Silicon, Si – A Metalloid Silicon has metallic luster Silicon is brittle like a nonmetal Silicon is a semiconductor of electricity Other metalloids include: Boron, B Germanium, Ge Arsenic, As Antimony, Sb Tellurium, Te
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Main Group Elements Transition Metals Inner Transition Metals Blocks Blocks
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very reactive metals that do not occur freely in nature malleable, ductile, good conductors of heat and electricity. softer than most other metals, can be cut with knife React violently with water (explode) React with halogens to create salts ALKALI METALS
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Very reactive metals not found free in nature harder, denser, and stronger than alkali metals Have higher melting points than group 1, and are less reactive ALKLINE EARTH METALS
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ductile and malleable, and conduct electricity and heat iron, cobalt, and nickel, are the only elements known to produce a magnetic field. TRANSITION METALS
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RARE EARTH ELEMENTS many are man-made
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OTHER METALS are ductile and malleable solid, have a relatively high density, and are opaque
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METALLOIDS have properties of both metals and non- metals some of the metalloids, such as silicon and germanium, are semi-conductors. This property makes metalloids useful in computers and calculators
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NON-METALS not able to conduct electricity or heat very well very brittle, and cannot be rolled into wires or pounded into sheets exist in two of the three states of matter at room temperature: gases (such as oxygen) and solids (such as carbon). have no metallic luster, and do not reflect light.
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HALOGENS "halogen" means "salt-former" and compounds containing halogens are called "salts" exist in all three states of matter: Solid- Iodine, Astatine Liquid- Bromine Gas- Fluorine, Chlorine
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NOBLE GASES do not form compounds easily Very unreactive due to their octet
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Noble Gases Noble Gases
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Special elements Hydrogen and Helium are special b/c although they share some characteristics with their groups/families, they are different b/c they have properties that are not similar to those of ANY group Hydrogen and helium are the simplest and most abundant elements. Hydrogen makes up 76% of the mass of the universe and helium makes up 23%
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Aspirin Aspirin
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Half of the distance between nuclei in covalently bonded diatomic molecule "covalent atomic radii" Periodic Trends in Atomic Radius Radius decreases across a period Increased magnetic attraction Radius increases down a group Addition of principal quantum levels Determination of Atomic Radius:
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Table of Atomic Radii
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Tends to increase across a period Atoms become closer to a full electron octet in the outer energy level Tends to decrease down a group Outer electrons are farther from the nucleus Ionization Energy - the energy required to remove an electron from an atom Ionization Energy - the energy required to remove an electron from an atom
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Table of 1 st Ionization Energies
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Ionization of Magnesium Mg + 738 kJ Mg + + e - Mg + + 1451 kJ Mg 2+ + e - Mg 2+ + 7733 kJ Mg 3+ + e -
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Another Way to Look at Ionization Energy
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Electronegativity A measure of the ability of an atom in a chemical compound to attract electrons Electronegativities tend to increase across a period (full octet) Electronegativities tend to decrease down a group or remain the same
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Periodic Table of Electronegativities
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Summation of Periodic Trends
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