Transcript PPT format
Chapter 3 Chemical Periodicity and The Formation of Simple Compounds 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 Groups of Elements The Periodic Table Ions and Ionic Compounds Covalent Bonding and Lewis Structures Drawing Lewis Structures Naming Compounds in Which Covalent Bonding Occurs The Shapes of Molecules Elements Forming More than One Ion Topics to be emphasized in Exam 1 Chapter 3 Chemical Periodicity. Formation of Simple Compounds. Molecular Structure. Section 3.2 The Periodic Table Section 3.3 Covalent Bonding Section 3.3 Lewis Structures Section 3.4 Shapes of Molecules Section 3.2 Periodic Table (1) Classic exemplar of the scientific process: Mendeleev (2) Atomic mass and atomic number as atom identifiers (3) Periodic properties along rows and down columns Electronegativity (ability of an atom to hold electrons) Chemical reactivity (kinds of reactions atoms undergo) Valence (the number of bonds to other atoms) (4) Underlying structure of the Periodic Table is the electronic structure of atoms not their masses. Dmitri Mendeleev Biological Periodic Table http://umbbd.ahc.umn.edu/ periodic/spiral.html Alternate forms of the periodic table: http://www.wou.edu/las/physci/ch412/alttable.htm The Periodic Table (1) The chemical and physical properties of the element are periodic functions of their atomic masses. (2) The chemical and physical properties of the elements are periodic functions of the atom number (number of protons in the nucleus = number of electrons in the neutral atom). (3) The elements can be arranged in groups (columns) of elements that possess related chemical and physical properties. (4) The elements can be arranged in periods (rows) of elements that possess progressively different physical and chemical properties. The Table by groups I II III IV V VI VII VIII Groups of Elements in the Periodic Table Eight Groups (the representative elements): I. Alkali metals: II. Alkali earth metals: III. Boron family: IV. Carbon family: V. Nitrogen family: VI. Chalcogens VII.Halogens VIII. Noble gases: (H), Li, Na, K, Rb, Cs Be, Al, Ca, Sr, Ba, Ra B, Al, Ga, In, Tl C, Si, Ge, Sn, Pb N, P, As, Sb, Bi O, S, Se, Te, Po F, Cl, Br, I, At (He), Ne, Ar, Kr, Xe, Rn The Table by “kinds” of elements The Table by “sizes” of atoms The Table by atomic radius The connection between the Periodic Table and atomic structure. Valence electrons: The electrons which are furthest from the positive nucleus and are most loosely held. These electrons determine chemical properties of elements and molecules. Periodic Table: The group number of the group of a column for the main group elements in the periodic table is the number of valence electrons possessed by the neutral atom = atomic number = number of protons in the nucleus of an atom. Group number (GN for main group elements) = number of valence electrons Valence electrons for elements 1-18 I II III IV V VI VII 1H VIII 2He 3Li 4Be 5B 6C 7N 8O 9F 10Ne 11Na 12Mg 13Al 14Si 15P 16S 17Cl 18Ar The Table by electron affinity (energy released when an electron is added to an atom Electronegativity and electron affinity are two key features which determine the nature of the chemical bond. More later….