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Periodic Table of Elements Bohr Model: and Valence electrons http://youtu.be/trsln8RCEVo Casseopia http://youtu.be/5MMWpeJ5dn4 Dan Radcliffe http://youtu.be/rSAaiYKF0cs Bald Guy: http://youtu.be/nsbXp64YPRQ Song: http://youtu.be/afFw91fvNJM http://youtu.be/zGM-wSKFBpo Dmitri Mendeleev Russian chemist. Created first version of the periodic table. Predicted properties of elements yet to be discovered. Rockin the shaggy beard… Mendeleev arranged elements according to their atomic weights. Today they are arranged by atomic number. Periodic Law Properties of elements are periodic functions of their atomic numbers. In other words, properties tend to repeat as you start a new period. Groups/Families Columns on the table (1-18). Elements have the same number of valence electrons. Similar chemical properties. Tend to form bonds in a similar way to get stable octet. Periods (1-7) The rows on the table. Have the same number of occupied energy levels. They do not have similar properties. Get to Know Your Groups Alkali Metals 1 valence electron Form +1 Ions Very reactive Found only in compounds. Rubidium Comparing the Alkali Metals http://youtu.be/uixxJtJPVXk Alkaline Earth Metals 2 valence electrons Form +2 ions Very reactive Found only in compounds Halogens 7 valence electrons Form -1 ions Very reactive All nonmetals Gas Liquid FLUORINE Extremely reactive gas Solid IODINE solid → gas (sublimes) Noble Gases Inert Gases Not reactive Have stable octet (except He) Monoatomic gases s, p, d, f, “Blocks” Indicates what sublevel is being filled last in the atom Transition Metals Metals in the “lower” columns. (d-block metals) “Inner” transition metals are the two bottom rows (f-block metals) Transition Metals Form colored compounds and solutions. Metals/Nonmetals/Metalloids Metals Have luster Malleable Ductile Conduct heat and electricity Tend to lose valence electrons and form positive ions All solids (except Hg) Nonmetals No luster Brittle (if solid) Don’t conduct Tend to gain valence electrons and form negative ions Can be solid ( I, C, P, S) , liquid (Br), or gases (F, Cl, N, O) Hydrogen is considered a nonmetal Metalloids (Semimetals) Most elements along the “staircase” Can have properties of both metals and nonmetals. B, Si, Ge, As, Sb, Te, At Trends in the Period Table Atomic Radius Distance from the nucleus of an atom to the outer edge of it’s electron cloud. Get out Reference Table S Trends in Radius Li Na Down a Group K Ex: Group 1 What happens? Rb Cs Fr Across a Period Ex: Period 2 Li Be B What happens? C N O F Ne Down a Group Size increases Why? You add new energy levels Across a Period Size decreases Why? Increasing nuclear charge pulls on the energy levels http://youtu.be/ba2yN2HtPTA Ionization Energy Energy required to remove the outermost electron from an atom. Get out Reference Table S Trends in Ionization Energy Down a Group Ex: Group 1 What happens? Li Na K Rb Cs Fr Across a Period Ex: Period 2 Li Be B C What happens? N O F Ne What is the trend? Directly related to Atomic Radius. Large Radius = Lower Ionization Energy Why? The further the outmost electron to the nuclear pull the easier to remove it. http://youtu.be/8F9nA4Fg3Rw Electronegativity The relative attraction an atom has for electrons involved in bond formation. The higher the EN value the more the atom “pulls” on electrons involved in a bond. This can result in “polar” and “nonpolar” bonds. Fluorine has the highest EN value = 4 (The EN scale was created by comparing other elements to Fluorine) Get out Reference Table S Trends in Electronegativity Down a Group Ex: Group 1 What happens? Li Na K Rb Cs Fr Across a Period Ex: Period 2 Li Be B C What happens? N O F Ne http://youtu.be/93G_FqpGFGY Metallic/NonMetallic Character More “Metallic”: Large radius Low Ionization Energy Low Electronegativity More “Non Metallic”: Small radius High Ionization Energy High Electronegativity