The Periodic Table- Topic 5 Click for song SMB, Periodic Table Notes 2011

Click on pix for history SMB, Periodic Table Notes 2011

A. Dmitri Mendeleev (1869, Russian) I. HISTORY A. Dmitri Mendeleev (1869, Russian) Organized elements by increasing ATOMIC MASS. Elements with similar chemical properties were grouped together. There were some discrepancies. SMB, Periodic Table Notes 2011

SMB, Periodic Table Notes 2011 B. Henry Moseley ORGANIZED ELEMENTS BY INCREASING ATOMIC NUMBER. Resolved discrepancies in Mendeleev’s arrangement. SMB, Periodic Table Notes 2011

SMB, Periodic Table Notes 2011 When elements are arranged in order of INCREASING ATOMIC #, elements with similar chemical properties appear at regular intervals. SMB, Periodic Table Notes 2011

SMB, Periodic Table Notes 2011 II. ORGANIZATION OF THE ELEMENTS A. Arrangement of Table 1. Horizontal rows Called PERIODS All elements in the same period have the same number of ENERGY LEVELS in their atomic structure SMB, Periodic Table Notes 2011

SMB, Periodic Table Notes 2011 2. Vertical Columns Called GROUPS OR FAMILIES All elements in the same group have the same number of VALENCE ELECTRONS, therefore lose or gain the SAME number of electrons, form similar CHEMICAL FORMULAS and have similar CHEMICAL PROPERTIES ex. XCl2 Group 2: Be +2 Cl -1 = BeCl2 Mg +2 Cl -1 = MgCl2 Remember: When writing formulas, use the criss-cross rule to cancel out oxidation states SMB, Periodic Table Notes 2011

III. Comparing Metals, Nonmetals & Metalloids Elements on the Periodic Table are divided into three subgroups called METALS, NONMETALS and METALLOIDS (semimetals). Click on Increase metallic properties Increase nonmetallic properties Decrease metallic properties SMB, Periodic Table Notes 2011

SMB, Periodic Table Notes 2011 METALS: located on the LEFT SIDE of the periodic table (except H); MORE THAN 2/3 of all elements 1. Chemical properties tend to LOSE ELECTRONS EASILY have LOW IONIZATION ENERGY (energy needed to remove electrons) Metallic character INCREASES as ionization energy decreases. have LOW ELECTRON AFFINITY (attraction for electrons) form POSITIVE IONS when combining with other atoms FRANCIUM most reactive metal: See Table J http://castlelearning.com/review/reference/chem%20table%20j.htm SMB, Periodic Table Notes 2011

2. Metals Physical Properties good conductors of heat and electricity LUSTROUS - reflect light, shine when they are polished MALLEABLE - can be rolled or hammered into sheets DUCTILE - can be drawn into wires are SOLIDS at room temperature except for MERCURY (liquid) SMB, Periodic Table Notes 2011

SMB, Periodic Table Notes 2011 B. NONMETALS located on the right side of the periodic table (except for Noble gases) Chemical properties tend to GAIN electrons to form NEGATIVE IONS have high electron affinities (electronegativity) produce COVALENT bonds by SHARING electrons with other nonmetals FLUORINE most reactive nonmetal: see Table J SMB, Periodic Table Notes 2011

SMB, Periodic Table Notes 2011 2. Nonmetals Physical Properties exist as gases, molecular solids, or network solids at room temperature except BROMINE (liquid) BRITTLE - (shatters when struck) DULL - does not reflect light even when polished POOR CONDUCTORS of heat and electricity Allotropes: Different SHAPE & PROPERTIES forms from the same element. CARBON: coal; diamond, graphite OXYGEN: O2; O3 (OZONE) SMB, Periodic Table Notes 2011

SMB, Periodic Table Notes 2011 C. METALLOIDS Found lying on the jagged line between metals and nonmetals flatly touching the line (except Al and Po). B,Si,Ge,As,Sb,Te & At Exhibit properties of both metals and nonmetals Behave as nonmetals but their conductivity is like metals SEMICONDUCTORS – Si and Ge SMB, Periodic Table Notes 2011

SMB, Periodic Table Notes 2011 IV. Periodic Trends – use Table S A. Periodic Law When elements are arranged in order of increasing atomic #, elements with similar properties appear at regular intervals. http://castlelearning.com/review/reference/chem%20table%20s.htm SMB, Periodic Table Notes 2011

1) Ionization Energy Energy needed to remove the most loosely bound electron from a neutral gaseous atom X + energy X+ + e-

Trends in Ionization Energy 6.3 Trends in Ionization Energy First ionization energy tends to increase from left to right across a period and decrease from top to bottom within a group. Predicting Which element would have the larger first ionization energy—an alkali metal in period 2 or an alkali metal in period 4?

Trends in Ionization Energy IE increases as you move across a period Why? The nuclear charge (atomic #) is increasing therefore greater attraction of the nucleus for electrons hence harder to remove an electron

Trends in Ionization Energy IE decreases as you move down a group Why? Atom size increases making the outermost electron farther away from the nucleus therefore making it easier to remove Shielding increases

SMB, Periodic Table Notes 2011 © 1998 LOGAL 2. Atomic Radius ½ the distance between nuclei Decreases to the LEFT and Increases as you go DOWN Click on for video clip 1:07 SMB, Periodic Table Notes 2011

SMB, Periodic Table Notes 2011 Atomic Radius cont. Why is it larger going down? Higher energy levels have larger orbitals Shielding - core e- block the attraction between the nucleus and the valence e- Why is it smaller to the right? Increased nuclear charge without additional shielding pulls e- in tighter SMB, Periodic Table Notes 2011

SMB, Periodic Table Notes 2011 Comparison??? Why is the ionization energy opposite that of atomic radius? In small atoms, e- are close to the nucleus where the attraction is stronger Why small jumps within each group? Stable e- configurations don’t want to lose e- SMB, Periodic Table Notes 2011

SMB, Periodic Table Notes 2011 3. Electronegativity Click on for video clip 1:11 the ability for an atom to attract electrons (electron affinity) Based on a scale of 4, Fluorine having the greatest EN A. Metals lose e- Form Cations (+) get smaller B. Nonmetals gain e- Form Anions (–) Get larger © 2002 Prentice-Hall, Inc. SMB, Periodic Table Notes 2011

Trends in Electronegativity 6.3 Trends in Electronegativity Representative Elements in Groups 1A through 7A

4. Melting/Boiling Point – Table S Highest in the middle of a period. SMB, Periodic Table Notes 2011

Periodic Trends Summary (use reference Table S for data comparison) Across a period (L to R) Down a group Ionization energy increases decreases Electronegativity Atomic radii Metallic properties Click on for video clip 4:41 SMB, Periodic Table Notes 2011

SMB, Periodic Table Notes 2011 IV. Classification Alkali Metals Alkaline Earth Metals Transition Metals Halogens Noble Gases Click for song SMB, Periodic Table Notes 2011

SMB, Periodic Table Notes 2011 Group 1: Alkali Metals extremely reactive (not found free in nature) form stable ionic compounds react with water to form a base react with air to form oxides react with acids to form salts Click on for video clip SMB, Periodic Table Notes 2011

Group 2: Alkaline Earth Metals reactive (not found free in nature) - form stable ionic compounds react with water to form a base react with air to form oxides react with acids to form salts Click on for video clip SMB, Periodic Table Notes 2011

Groups 3-11: Transition Metals multiple positive oxidation states Lose electrons from two outermost energy levels Ions form colored solutions SMB, Periodic Table Notes 2011

Group 15 – unique features Members range from typical nonmetals (nitrogen and phosphorus) through metalloids (arsenic and antimony) to metals (bismuth) Nitrogen Forms stable diatomic molecules with a triple bond Component of protein Forms some unstable compounds that are used as explosives Phosphorus Component of nucleic acids (DNA, RNA) More reactive than nitrogen at room temperature SMB, Periodic Table Notes 2011

Group 16 – unique Features Members range from typical nonmetals (oxygen and sulfur) through metalloids (selenium and tellurium) to metals (polonium) Solids except oxygen Oxygen can exist as O2 and O3 (it is an allotrope) Polonium is radioactive SMB, Periodic Table Notes 2011

SMB, Periodic Table Notes 2011 Group 17: Halogens very reactive nonmetals - high electronegativity not found free in nature form diatomic molecules when free react with metals to form salts (halides) Found in all three phases (s, l, g) due to differences in Van der Waals forces (these are weak) SMB, Periodic Table Notes 2011

SMB, Periodic Table Notes 2011 Group 18: Noble Gases Have complete outer shells Almost inert (not reactive); stable Krypton, xenon, and radon form compounds with oxygen and fluorine Referred to as monatomic gases SMB, Periodic Table Notes 2011